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HomeUncategorizedphosphate group example

Chloramphenicol is bonded in the ester through its primary hydroxyl group. 6). The incorporated enzymes were shown to have improved thermal stability, with more than 50% of their activity preserved. Due to their phosphate groups, nucleic acids are negatively charged at all but the most acidic of pH conditions. Common biological targets of antiviral nucleosides are reverse transcriptases or RNA and DNA polymerases. We will see many examples of phosphate leave groups in this and subsequent chapters. Nucleosides are constituted by a purine or pyrimidine base which is linked to a furan moiety, often ribose or deoxyribose. The phosphate group of phospholipids shows a strong PO stretching band at 1350–1250 cm−l, which is sometimes a doublet and may be shifted to lower frequencies with an increase in intensity. The intercalation of these molecules into LDHs is thought to stabilize them physically, chemically, and biologically, and consequently we could expect longer half lives and lower dosage requirements (see Chapter 1.115, Calcium Phosphates for Cell Transfection). (da Silva and Williams). These groups play an important role in the formation of molecules like DNA, proteins, carbohydrates, and lipids. The spectrum of a solid phospholipid may show fine structure at low temperatures, which disappears on heating. Phosphates can be grouped as: primary phosphates that have crystallized from a liquid; secondary phosphates formed by the alteration of primary phosphates; and rock phosphates formed from phosphorous-bearing organic material. For example, as the main ingredient of signal transduction, ATP hydrolysis to ADP and inorganic phosphate (breaking a bond between two phosphates) is used in order to phosphorylate amino acids in proteins. This is the ester functional group. This substitution pattern is symmetric, and careful chemical and 31 P-n.m.r. The pathway I is the main route which produces the carboxylic iridoid form in major yield; it starts from iridodial skeleton which is oxidized to iridotrial form and consequently transformed into a series of iridoid glycosides, secoiridoids, including indole alkaloids [98,107–109]. Iridoids can be divided into four main groups: iridoid glucosides, simple iridoids, secoiridoids, and bisiridoids (Fig. Rietschel, in, Advances in Carbohydrate Chemistry and Biochemistry, Encyclopedia of Analytical Science (Second Edition), Anti-HIV Agents From Nature: Natural Compounds From Hypericum hircinum and Carbocyclic Nucleosides From Iridoids, Luigi Ornano, ... Armandodoriano Bianco, in, Anny-Odile Colson, Michael D. Sevilla, in, Biocompatibility, Surface Engineering, and Delivery of Drugs, Genes and Other Molecules. C.M. It is, however, an indirect method for the detection of phosphopeptides and a more detailed analysis of the native phosphopeptides by MS/MS is required to localize the exact phosphorylation sites. Phosphates can also be found in the backbone of DNA forming phosphodiester bonds (two esters with a common posphonylâ¦ Recently, it was clarified the significant role of iridoids as yield of isoprene units converted to iridoids involved in MEP pathway in comparison with MVA pathway. Other electrophoretic parameters, such as applied field strength and temperature, have an effect on the mobility of the different chain length nucleic acids and on the separation efficiency. This high resistance of the LDH against nuclease attack is highly advantageous and makes it a delivery material for DNA under physiological conditions where DNA degradation through nuclease attack can take place. As trivalent ions such as aluminum readily form stable complexes with the phosphates on the DNA backbone, it has been difficult to prepare DNA-LDH intercalates by direct coprecipitation. The four oxygen substituents in phosphate groups are arranged about the central phosphorus atom with tetrahedral geometry, however there are a total of five bonds to phosphorus - four s bonds and one delocalized $$\pi$$ bond. Similar to fatty acid intercalates, interlayer VA molecules appear to be arranged in a zig-zag orientation that maximizes their intermolecular π–π interactions. When the terminal anhydride bond of ATP is hydrolyzed, adenosine diphosphate (ADP) is produced and 30.5 kJ of energy are released per mole of ADP produced. Classes of iridoids have an important distribution within the Apocynaceae family, but they are concentrated in few genera, the most representative are Plumeria, Himatanthus, Allamanda, and Cerbera [148]. DNA-LDH or DNA alone, with the same initial optical density of 0.4 at 260 nm, were identically treated with 192 units of DNase I and DNA degradation by DNase I was estimated by the change in optical density at 260 nm recorded as a function of time (Figure 3). Their presence in the neighborhood of phosphate residues (or of Kdo in LPS) may be considered as a regulating factor, controlling the electrostatic interaction of negatively charged residues (phosphate) with such bivalent cations as Ca2 + or Mg2 + of the medium. Phosphate diesters have a $$pK_a$$ of about 1, meaning that they carry a full negative charge at physiological $$pH$$. an organic compound of phosphoric acid in which the acid group is bound to nitrogen or a carboxyl group in a way that permits useful energy to be released (as in metabolism). Structural variations of nucleosides and their analogues are briefly described later. Recall from section 8.4 that good leaving groups in organic reactions are, as a rule, weak bases. When attatched, confers on a molecule the ability to react with water, releasing energy (ATP / ADP) Phosphate mineral, any of a group of naturally occurring inorganic salts of phosphoric acid. Note that these esters are also acids. Gordon, in Encyclopedia of Analytical Science (Second Edition), 2005. Arrange A-S into groups of drawings that depict the same species (for example, group together all of the abbreviations which depict ATP). After the phosphate group is transferred, ADP and the new phosphoprotein are released. Phosphate Groups Can Activate Proteins. Each of these groups have functional properties ideal for many applications. Following dephosphorylation, complete inactivation of the enzyme is essential if the subsequent ligation reaction is to work efficiently. That is why phosphoric acid derivatives are soluble in the aqueous environment of cells. Iridoids are typical secondary metabolites of the plant kingdom, but they are not widespread everywhere; they are characteristic of angiosperms, in particular of the superorder of Sympetaleae [97]. Phosphate group: A functional group characterized by a phosphorus atom bonded to four oxygen atoms (three single bonds and one double bond). Different abbreviations are used. The large electrostatic perturbation can affect association processes of the phosphopeptide or phosphoprotein by increasing the electrostatic steering forces and/or alter protein structure and interactions. Given the structure of the ester, write the structure of the antibiotic. Even though the phosphate group in the DNA backbone offers a potential hole localization site, there is no experimental evidence for phosphate-centered radical cations with low LET radiations [113]. Phosphorus can break the 'octet rule' because it is on the third row of the periodic table, and thus has $$d$$ orbitals available for bonding. Nevertheless, the corresponding potential use of nucleosides in therapy is not simple due to several factors: Many nucleoside analogues are not effectively phosphorylated by cellular kinases during the hydrolysis of the nucleoside-base bond C1-base, consequently the C1–C6 bond of the furan ring opens, and the resultant metabolites (especially those not identified) can be potentially toxic. Nucleosides and nucleotides are evolutionary well-conserved molecules that are essential for living organisms. In organic chemistry, a phosphate is an ester, in which theâ¦ MS is a convenient technique to monitor such reactions because mass determination provides direct evidence of the enzyme catalyzed addition or removal of modifying groups [30,31]. A phospholipid is a type of lipid molecule that is the main component of the cell membrane. The backbone of DNA is linked by phosphate diesters. The biological stability of DNA in a DNA-LDH intercalate can be quantitatively evaluated using a DNase I resistance test. If a phosphate group is attached at the 5'position, it becomes deoxyguanosine monophosphate. For effective protection and controlled delivery, vitamin C (VC) or E (VE) molecules were intercalated into ZnAl-LDH42 or ZBSs.59 The X-ray diffraction patterns (Figure 5(a)) for the pristine LDHs (host LDHs before intercalation) and LDH intercalates exhibit well developed (00 l) reflections showing d-spacing of 8.7, 10.5, and 53.8 Å for pristine, VC-LDH and VE-LDH, respectively. The IR spectra of complex lipids are not sensitive to variations in acyl chain length, unsaturation, or the presence of α,β-unsaturated ether links. As natural source of chiral cyclopentane ring, the iridoids result variously substituted, enantiomerically pure and pose good chemical flexibility for a suitable convergent synthesis to give carbocyclic nucleoside analogues in comparison with furan derivatives, which are the principal building blocks employed for the synthesis of nucleoside analogues [151–157]. Thus, under constant applied electric field, the mobility is determined primarily by the pore size of the gel matrix. Table 2. Conversely, the separation and analysis of nucleic acids can be tuned by selection of an appropriate matrix and composition (Table 1). It was notable that, in this chapter, molecular orientation and stabilization could be determined by the type of lattice (Figure 6B (a) and (b)). In this interesting example the glycosylic position [GlcN(I)] and the hydroxyl group at C-4â² [GlcN(II)] both carry Etn-PP. Infrared spectroscopy revealed that the IAA molecules are more tightly bound to a ZBS layer than to an LDH. The truth about phosphates is something that needs to be clarified, because there are a lot of opinions out thereâours included. Clearly, an understanding of phosphate chemistry is central to the study of biological organic chemistry. Separate chapters list protection for the hydroxyl group, phenols and catechols, the carbonyl group, the carboxyl group, the thiol group, the amino group, and the phosphate group. H = 5.5; G = 9 to 9.7; no cleavage; contains uranium, radium, etc. Different abbreviations are used. Choi, in Comprehensive Biomaterials, 2011. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. The chemical linkage between phosphate and a carbon atom is a phosphate ester. [97], the iridoids are found into Lamiids, which contain iridoids of Gentianales, Lamiales Gallyales order, and into Campanulids, which contain secoiridoids of Asterales and Dipsacales order. In organic chemistry, a phosphate is an ester, in which the hydrogen in the compound's carboxyl group is replaced with a hydrocarbon group. Recently, a phosphorus centered radical produced by the fragmentation of a P-O bond was identified at low yield (about 0.1% of all radicals) in high LET studies with heavy ion beams [114]. The ester carbonyl frequency and bands between 670 and 1050 cm−1 may shift due to the variations in the crystal structure arising from different polymorphs. Figure 5. CIP can either be inactivated by proteinase K or by heating to 65 °C for 1 h or 75 °C for 10 min. Moreover, it has been postulated that positively charged groups in lipid A, such as l-Arap4N, significantly contribute to the resistance of certain Gram-negative bacteria (for instance P. mirabilis) to such antibiotics as polymyxin B (125). Free amine groups as present in phosphatidylserine or phosphatidylethanolamine show a single sharp absorption band at 1075 cm−l. One of these oxygen atoms must be bonded to another atom; if not, the structure is a phosphate ion. Did you know there are many different types of phosphates? The phosphate group connects successive sugar residues by bridging the 5â²-hydroxyl group on one sugar to the 3â²-hydroxyl group of the next sugar in the chain. Reproduced from Choy, J. H.; Jung, J. S.; Oh, J. M.; Reproduced from Yang, J. H.; Han, Y. S.; Park, M.; Park, T.; Hwang, S. J.; Choy, J. H. Atomistic Modelling of Phosphopeptide Recognition for Modular Domains, Annual Reports in Computational Chemistry. Draw all of the resonance structures showing the delocalization of charge on a (fully deprotonated) organic monophosphate. In inorganic chemistry, the phosphate ion combines one phosphorus atom with 3 or 4 oxygen atoms, forming the base for many different salts. 6.10. This template can be modified by modifying the sugar ring and/or heterocyclic base linked on C-1. Organic phosphates. The substitution of phosphate groups is often nonstoichiometric, as exemplified with N. meningitidis lipid A (Fig. The phosphate groups of nucleotides may be replaced by isosteres, the replacement of the base portion is often exploited in the development of structure–activity relationship (SAR) [170]. For a small, spherical particles, the balance of electric and viscous forces results in an electrophoretic mobility (u, defined as the particle velocity per applied electric field strength) given by. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Adenosine triphosphate (ATP), a triphosphate ester of adenosine, stores some of the energy released in the degradation of carbohydrates, fats, and amino acids. A partial loss of phosphate (HPO3, 80 Da) is seen in MALDI reflector TOF MS in the case of tyrosine phosphorylated peptides [30,36]. Gel purification followed by DNA precipitation is once again required following dephosphorylation. MS also enables the detection of phosphopeptides and phosphoamino acid residues by their ‘diagnostic’ metastable decomposition via gas phase β-elimination of phosphoric acid during time-of-flight mass analysis [35–37]. The X atom is typically O, C, NR, or S. It should be noted that relatively small changes in the structure can cause different biological, chemical (stability, reactivity), physical (solubility) effects, minor changes in the structure produce relevant, and diverse biological effects [99–101]. Based on the name of the drug, what is the name of the acid? Separation ranges for agarose and acrylamide gels, John D. Pickert, Benjamin L. Miller, in Comprehensive Natural Products Chemistry, 1999. Besides DNA, large biopolymers such as polysaccharides and proteins can be intercalated into LDHs. The ones of neplanocin A and aristeromycin were the first carbocyclic natural template involved carbocyclic nucleoside analogues syntheses [99–101]. Organic phosphates are often abbreviated using '$$OP$$' and '$$OPP$$' for mono- and diphosphates, respectively. Some of the important functional groups in biological molecules include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups. Hole stabilization on the phosphate group is therefore unlikely because transfer to the sugar and bases is energetically downhill. A functional group can participate in specific chemical reactions. Choy, ... S.J. A convergent synthesis could be schematized in two main steps; the first step deals with a modification of the iridoid backbone to give the new carbocyclic intermediate; the following step is the heterocyclic base link to the new carbocyclic backbone. In this method, the logarithm of the electrophoretic mobility is plotted as a function of gel concentration. The carbon atom chain to the right of the carbonyl group is part of the acid. Iridoids are the most numerous family of cyclopentane monoterpene derivatives present as secondary metabolites in the plant kingdom. A total of 16 carbon atoms are contained in palmitic acid. First, locate the ester functional group by examining the carbonyl carbon atoms. of the polypeptide. Rietschel, in Advances in Carbohydrate Chemistry and Biochemistry, 1994. We have recently reported the intercalation of folic acid and its derivatives into LDHs for use as a drug stabilization and delivery system.31 Folic acid (N-(4-{[(2-amino-4-oxo-1,4-dihydropteridin-6-yl)methyl]amino}benzoyl)-l-glutamic acid) and its derivative, folinic acid ((S)-2-[4-[(2-amino-5-formyl-4-oxo-5,6,7,8-tetrahydro-1H-pteridin-6-yl)methylamino] benzoyl]aminopentanedioic acid) are used in cancer therapy and in the treatment of vitamin deficiencies. Below are images of a nucleotide monophosphate(A) and a phosphoserine (B). The Phosphate Class is made up of minerals with a basic chemical unit of tetrahedral (AO4) groups with a negative three (-3) charge.The A can be either Phosphorus, Arsenic, Vanadium or Antimony. This is done for the sake of simplification - however it is important always to remember that the phosphate group is really tetrahedral, the negative charges are delocalized over the non-bridging oxygens, and that there is some degree of protonation at physiological $$pH$$ (with the exception of the phosphate diester group). A phosphate group functions as part of energy-storing molecules, has an important role in the regulation of cellular metabolism, and is even a constituent of DNA and RNA. For each compound, specify the number of bridging and non-bridging oxygens in the phosphate group. Luigi Ornano, ... Armandodoriano Bianco, in Studies in Natural Products Chemistry, 2018. Phosphate groups are attached to proteins and peptides by protein kinases. In DNA, the five-carbon sugar is deoxyribose, while ribose is the pentose sugar in RNA. These acid constant values, along with the Henderson-Hasselbalch equation ( section 7.2) tell us that, at the physiological $$pH$$ of approximately 7, somewhat more than half of the phosphate species will be in the $$HPO_4^{-2}$$ state, and slightly less than half will be in the $$H_2PO_4^{-1}$$ state, meaning that the average net charge is between -1.5 and -2.0. A good example of transferring energy is the three phosphate group which is found in the energy compound ATP(adenosine triphosphate). Neplanocin A and aristeromycin A. Like phosphoric acid, the phosphate group is prone to losing hydrogen ions and thus is both an acid and prone to taking on a negative charge. Adenosine monophosphate (AMP) has a single phosphate ester linkage. The contribution supplied from the iridoids in these two pathways is not yet clear. An organic diphosphate has two bridging oxygens (one in the phosphate ester linkage and one in the phosphate anhydride linkage) and five non-bridging oxygens: A single phosphate is linked to two organic groups is called phosphate diester. For example, glucose-6-phosphate and isopentenyl diphosphate are often depicted as shown below. Extraction and isolation methods from plant organisms is well known for a good number of iridoid glycosides. In laboratory organic reactions, leaving groups are often halides or toluenesulfonates (section 8.4), both of which are weak bases. Phosphoserine and phosphothreonine residues undergo partial gas phase β-elimination of phosphoric acid (H3PO4, 98 Da), in MALDI-TOF-MS and ESI-MS resulting in conversion into dehydroalanine residue (69 Da) and dehydroaminobutyric acid residue (83 Da), respectively. Adenosine triphosphate has one phosphate ester linkage and two phosphate anhydride linkages. The Phosphate Mineral Group includes a number of the rarer minerals and apatite. IAA is a type of plant auxin and has great potential as a prodrug or as a cosmetic or dermatological ingredient. 6.11. The infrared spectra of solid phospholipids vary due to the occurrence of polymorphism. This is an amide group, a very stable acyl functional group. These compounds are analogs of acid anhydrides of carboxylic acids. Nucleosides, nucleotides, and analogues are interesting molecules for scientists in almost all natural sciences. Just as alcohols react with carboxylic acids, they also react with phosphoric acid, pyrophosphoric acid, and. Phosphate group Definition noun, plural: phosphate groups ( biochemistry ) A functional group or radical comprised of phosphorus attached to four oxygen , and with a net negative charge, thus represented as PO 4 â Supplement The phosphate group is important in living things in different ways. Many CG models have been proposed over the years, for example, see refs. Therefore, it can be concluded that the intercalated DNA becomes more twisted than free DNA in order to fit into the available area in the LDH lattice (Figure 2(a)). Drug molecules and other biofunctional molecules require stabilization because they can easily be destroyed or expelled by various drug-resistant mechanisms in biological systems. A Phosphate Group Nitrogenous bases include purine molecules (adenine and guanine) and pyrimidine molecules (cytosine, thymine, and uracil.) Despite this interesting method of resolution of mixtures of iridoids and the pharmaceutical interest addressed to iridoids, there are few scientific papers which face this kind of purification way [97–158]. Its palatability for children is improved by using a suspension of the palmitate ester. Explain why the second $$pK_a$$ of phosphoric acid is so much higher than the first $$pK_a$$. Arrange A-S into groups of drawings that depict the same species (for example, group together all of the abbreviations which depict ATP). Similarly, an MS-based phosphatase assay is a useful tool to identify phosphopeptides in crude peptide mixtures generated by enzymatic proteolysis of phosphoproteins [13,34,35]. Reception 1 Transduction 2-6 Response 7 12. Iridoid glucosides (R = glucose), simple iridoids, secoiridoids, and bisiridoids. The introduction of a phosphate group generally carries a − 2 charge at physiologically pH. When two phosphate groups are linked to each other, the linkage itself is referred to as a 'phosphate anhydride', and the compound is called 'inorganic pyrophosphate' (often abbreviated $$PP_i$$). Two enzymes that are commonly used for dephosphorylation reactions are calf intestinal alkaline phosphatase (CIP)115 or bacterial alkaline phosphatase (BAP);116,117 in both cases, the reaction is typically allowed to proceed for 30 min at 37 °C. However, the nitrogenous bases of phospholipids can be identified by their IR absorption spectra in the region of 900–1100 cm−1. This is similar to the behavior observed with soaps and is due to the flexing and twisting of the hydrocarbon group on heating. The synthesis of new carbocyclic nucleoside analogues produces two important contributions: (1) it provides potential new drugs to be used as therapeutic interventions in combination therapies with other drugs and (2) libraries analogues with antiviral activity can be used to study the SAR, in order to understand the role they play during the biochemical processes. Recently, however, Desigaux et al.52 succeeded at intercalating DNA fragments of various sizes (100–500 and 6000–8000 bp) into an MgGa-LDH through coprecipitation. In the resonance contributors in which the bridging oxygens are shown as double bonds (to the right in the figure below), there is an additional separation of charge - thus these contributors are minor and make a relatively unimportant contribution to the overall bonding picture. Which could be described as an organic diphosphate? CLA alone, stored in a 50 °C chamber, completely decomposed in 7 days, while intercalated CLA exhibited long term thermal stability, for 49 days at 50 °C. The result is a free-floating phosphate plus ADP , or adenosine diphosphate (meaning it only has two phosphate â¦ 6.9. In inorganic chemistry, the phosphate ion combines one phosphorus atom with three or four oxygen atoms, forming the base for many different salts. At some temperature below the melting point of the lipid, the fine structure disappears completely due to movement of the acyl chain. The main idea was to employ a secondary metabolite which showed a variously functionalized cyclopentane, with a chemical function suitable for the heterocyclic base insertion. According to Model 2, what class of enzymes performs phosphorylation? Similarly, an enzyme, called phosphofructokinase, uses ATP to add a phosphate group to fructose-6-phosphate to form fructose-1,6-diphosphate. Similar thermal stability was observed with GLA intercalates; the intercalated GLA preserved 50% of its fatty acid moieties after 28 days at 50 °C, whereas all unprotected GLA molecules were oxidized after 14 days in the same chamber. At physiological pH, the protons in the –OH groups of these esters are ionized. For analytical purpose, identification and quantification involve GC-FID and GC-MS, which identify a specific iridoid glycoside by using its original fragmentation pattern correlated with the relative retention time. Being a natural resource, this metabolite is enantiomerically pure, defined chiral template because it is synthesized by biosynthetic pathway employing enzymes. Another folate derivative, methotrexate (MTX: (2 S)-2-[(4-{[(2,4-diamino-7,8-dihydropteridin-6-yl)methyl] (methyl)amino}phenyl)formamido] pentanedioic acid), is known to act as a folic acid antagonist and inhibits the proliferation of certain cancers by regulating the biosynthesis of thymidylate.56,57 Unfortunately, these are quite unstable in biosystems, with short plasma half lives of 6.2 h and 3–15 h (depending on dose) for folinic acid and MTX, respectively. The intercalation of therapeutic genes, such as antisense oligonucleotides, into LDHs has also been reported.13 Thyveetil et al.53 computed the stability of DNA-LDH intercalates utilizing molecular dynamics simulations and showed that the phosphate backbone exactly aligns with the lattice of the trivalent ions. When many phospholipids line up, they form a double layer that is characteristic of all cell membranes. By continuing you agree to the use of cookies. Similarly, removal of phosphate groups by the action of phosphatases results in a mass decrease of 79.97986 or multiples thereof. The trans double bond of sphingosine derivatives gives an absorbance band at 970 cm−1, although another band occurs at this frequency in some sphingosine derivatives such as sphingomyelin and this interferes with the use of this band for quantitative determination of the trans unsaturated content. glycerol phosphate. Recently, the intercalation procedure has been employed in food science to increase the stability and applicability of additives. It is noteworthy that most of the substituents on the phosphate, such as Etn, l-Arap4N, and GlcpN carry, at neutral pH, a positively charged amino group. The fully deprotonated conjugate base of phosphoric acid is called a phosphate ion, or inorganic phosphate (often abbreviated '$$P_i$$'). In DNA and RNA, a phosphodiester group (in the black circle) joins the 3'-carbon on the ribofuranose of one nucleobase to the 5'-carbon on the next nucleobase. Phosphate groups also contain a negative charge and can participate in ionic bonds. Gentianales order includes four families called Apocynaceae, Gentianaceae, Loganinaceae, and Rubiaceae (APG III, 2009), highlighting the diversity of the composition of iridoids in these five families. Phosphate groups are common in nucleic acids and on phospholipids (the term "phospho" referring to the phosphate group on the lipid). In the hybrid orbital picture for phosphate ion, a single $$3s$$ and three $$3p$$ orbitals also combine to form four $$sp^3$$ hybrid orbitals with tetrahedral geometry. Again, specify the number for each answer. Phosphate minerals contain the tetrahedrally coordinated phosphate (PO 4 3â) anion along sometimes with arsenate (AsO 4 3â) and vanadate (VO 4 3â) substitutions. Since the tails are hydrophobic, they face the inside, away from the water and meet in the inner region of the membrane. These groups play an important role in the formation of molecules like DNA, proteins, carbohydrates, and lipids. the trivalent anion PO43â derived from phosphoric acid H3PO4. Lipids are molecules that include fats, waxes, and some vitamins, among others. About 30 nucleoside analogues are approved as drugs [159]. where q is the charge on a particle of radius R and η is the solvent viscosity. Most complex lipids are acylglycerol derivatives and therefore their IR spectra show bands characteristic of esters and hydrocarbon chains (Table 2). 9.1: Prelude to Phosphate Transfer Reactions, 9.3: Phosphate Transfer Reactions - An Overview, Organic Chemistry With a Biological Emphasis. These values are smaller than the longitudinal molecular dimensions of folic acid (≈ 19.7 Å), folinic acid (≈ 21.5 Å), and MTX (≈ 21.2 Å). Table 1. The mechanisms of action of both purine and pyrimidine nucleoside analogues are similar. Restriction digest creates free phosphate groups on the 5′ ends of the DNA. Based on the longitudinal dimensions of the vitamin molecules and the observed gallery space, a schematic illustration of the vitamin-LDH structures are shown in Figure 5(b). It was also verified, using UV–vis spectroscopy, that α-(+)-tocopherol acid succinate molecules stack diagonally with respect to the basal plane, suggesting that the stabilization of vitamin molecules occurs via electrostatic interactions. These results suggest that the intercalated molecules are oriented in a tilted monolayer with tilt angles of ∼60°, 42°, and 45° between the LDH layer and folic acid, folinic acid, and MTX, respectively (Figure 4(b)).31 Assuming that these molecules are packed in a zig-zag, the electrostatic interactions between the anionic terminal carboxylates and the cationic hydroxide layers can be maximized. It was shown that the wave number difference between two stretching modes of carboxylate, Δνas-s = νas(COO−) − νs(COO−), became larger when it was coordinated to a metal.64–66 As described by Yang et al., the Δν value for Na+-IAA, IAA-LDH, and IAA-ZBS were determined to be 161, 162, and 179 cm−1, respectively.