Biological Syntheses

The biosynthesis of polysaccharides is not a straightforward reversal of the hydrolysis process, because the direct polycondensation of monosugars in an aqueous environment produces a positive Gibbs energy. Instead, biosynthesis occurs when a monosugar joins onto the nonreducing end of what is called a primer  

For cellulose synthesis, guanosine diphosphate is necessary instead of UDP. Adenosine triphosphate or Cori ester is also used for in vitro syntheses. The polycondensation of simple monosugars can also be carried out with the aid of condensation products of ethers with phosphorus pentoxide. 

The production of D-glucose-1-phosphate as an intermediate does not seem to be necessary in other polysaccharide syntheses. Cane sugar (sucrose, saccharose), for example, is converted by the action of the enzyme dextran saccharase into dextran, a poly(glucose), with fructose as by-product. Another product of saccharose is levane, a poly(fructose) produced by the action of the enzyme levane saccharase through release of glucose. 

The chemical synthesis of polysaccharides is an acetal synthesis, formally between the hemiacetal function at C-1 and any one of the hydroxyl groups of another sugar unit. It can occur either in stages through con- 

For the synthesis of glycogen-type polysaccharides from a-n-glucopyran-osyl phosphate, two enzymes are required. Phosphorylases, in presence of a suitable primer, synthesize linear chains of -( — 4)-linked n-glucose residues these are then converted into a branched polysaccharide by a branching enzyme.  

A synthesis of glycogen in vitro was reported by Stepanenko and co-workers, who incubated a-n-glucopyranosyl phosphate and a small 

The sjmthetic glycogens, which contained about 94% of anhydro-n-glucose, 4-6% of moisture, and 0.1% of nitrogen and phosphorus, are similar to ex vivo glycogens, except that the degree of branching appears to be slightly less. 

Liver glycogen is synthesized from D-glucose in vivo by the enzyme system hexokinase-phosphoglucomutase-phosphorylase-branching enzyme (see Fig. 3). Glycogen is also formed from D-galactose and D-mannose 

Sample Molecular weight X 10 C.L. fi-Amyl-olysis limit, % Iodine complex, absorption spectrum  

Anserine was first isolated in 1929 from extracts of goose-flesh by Ac-kermann, Timpe, and Poller (13). By various degradation reactions, Lin-neweh, Keil, and Hoppe-Seyler (385), Keil (342), and Linneweh and Lin-neweh (386) demonstrated that anserine is monomethylcarnosine. The synthesis of anserine from L-l-methylhistidine and /3-alanine by Behrens and du Vigneaud (54) clearly established its structure. 

Another procedm-e permitting a more rapid isolation of the copper salt of anserine is that of Deutseh, B leton, and Eggleton (165). 

The same diketopiperazine was recently isolated by Kuizenka et al. (360) from pig adrenal cortex. No physiological, hormonal, or other activity has been found for this peptide (636). 

The same peptide was isolated by Johnson et al. (324) from culture filtrates of an unidentified species of Streptomyces, and also from Strepto-myces griseus, and Aspergillus fumigatus H.S. The two latter are streptomycin-producing strains. The peptide appears in the culture mediumjonly after growth and is isolated in crystalline form. The cyclic peptide has been identified by its infrared spectrum and by its hydrolysis products, which were identified by paper chromatography. Isolation of leucine and proline and the determination of their rotatory power have shown that they are both in l form. 

Butenandt et al. (104) isolated from the chrysalis of silkworm (Bom-byx mori) 4 diketopiperazines the anhydride of L-leucyl-L-proline, identical to the previously described substance, and the anhydrides of valylpro-line, of alanylproline, and of leucylalanine. It should be noted that 3 of these 4 compounds contain proline. 

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Prepn Weiss and Stekol J Am Chem Soc 73 2497 I95I see also du Vigneaud et al. J Biol Chem 143 60 1942 Biological synthesis Greenberg Methods Enzymol 5 943 1962.]... 

Biological Synthesis of Carbohydrates. Third Frankland Memorial Lecture, J. R. Inst. Chem., 79 (1956)591-592. 

Siegel S.M. (1957) Non-enzymic macromolecules as matrices in biological synthesis. The role of polysaccharides in peroxidase catalyzed lignin polymer formation from eugenol // J. Amer. Chem. Soc. V. 79. P. 1628-1632... 

Granik, S., Magnesium vinyl pheoporphyrin another intermediate in the biological synthesis of chlorophyll, J. Biol Chem., 183, 713, 1950. 

Song, J.Y. and Kim, B.S. (2009) Rapid biological synthesis of silver nanoparticles using plant leaf extracts. Bioprocess and Biosystems Engineering, 32, 79-84. 

Matching chemical procedures with biological synthesis ... 

Shankar, S.S., Rai, A., Ankamwar, B., Singh, A., Ahmad, A., Sastry, M. 2004. Biological synthesis of triangular gold nanoprisms. Nature Mater. 3, 482-488. 

Polyene cyclizations have been of substantial value in the synthesis of polycyclic natural products of the terpene type. These syntheses resemble the processes by which terpenoid and steroidal compounds are assembled in nature. The most dramatic example of biological synthesis of a polycyclic skeleton from a polyene intermediate is the conversion of squalene oxide to the steroid lanosterol. In the biological reaction, the enzyme presumably functions not only to induce the cationic cyclization but also to bind the substrate in a conformation corresponding to the stereochemistry of the polycyclic product.21... 

Livesey PJ (1986) Learning and emotion a biological synthesis. Lawrence Erlbaum, Hillsdale Lucki 1, Dalvi A, Mayorga AJ (2001) Sensitivity to the effects of pharmacologically selective antidepressants in different strains of mice. Psychopharmacology (fieri) 155 315-322 Martin P (1998) Animal models sensitive to anti-anxiety agents. Acta Psychiatr Scand Suppl 393 74-80... 

Sastry M, Shankar SS, Rai A, Ankamwar B, Singh A, Ahmad A (2004) Biological Synthesis of Triangular Gold Nanoprisms. Nat Mater 3 482-488... 

Arginine Is the Precursor for Biological Synthesis of Nitric Oxide... 

Phenanthroline has been patented as a useful enzyme inhibitor during the biological synthesis of prostaglandins.532... 

Catabolism involves pathways composed of enzymes and chemical intermediates that are involved primarily in the breakdown of large molecules into small molecules, often by oxidation processes. Anabolism is the collection of the enzymes and chemical intermediates involved in the biological synthesis of larger molecules from smaller molecules. Anabolism often involves reduction processes. 

Tetr 39 2323 (1983) (Recent Advances in the Preparation and Synthetic Applications of Oxiranes) 43 3309 (1987) (Synthetic Routes to Tetrahydrofuran, Tetrahydropyran, and Spiroketal Units of Polyether Antibiodcs and a Survey of Spiroketals of Other Natural Products) SO 8885 (1994) (Chemical and Biological Synthesis of Chiral Epoxides)... 

A significant number of tryptophan and tryptamine chemical syntheses are known this section describes their biological synthesis in vivo (whole cells), the in vitro enzymatically catalysed synthesis and synthesis through chemo-enzymatic approaches. 

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