Dehydrogenations biochemical

A similar conversion of a bis-primary diol into a lactone is achieved by biochemical dehydrogenation (equation 295) [1035]. 

Kawaguchi A, S Tsubotani, Y Seyama, T Yamakawa, T Osumi, T Hashimoto, Y Kikuchi, M Ando, S Okuda (1980) Stereochemistry of dehydrogenation catalyzed by acyl-CoA oxidase. J Biochem 88 1481-1486. 

Enzymatic Dehydrogenation Experiments. Arch. Biochem. Biophysics 31, 300 (1951). 

Smith, V. M. On the Mechanism of Enzyme Action. XXXVI. Dehydrogenation Studies on Merulius lacrymans and Marasmius chordalis and the Mechanism of Oxalic Acid Formation. Arch. Biochem. 22, 275 (1949). 

Part 28. Application of Resazurin to the Study of Dehydrogenations by Certain Merulii and Pomes annosus. Arch. Biochem. 9, 439 (1946). 

Adams, P.R., Harrison, R., and Inch, T.D., Dehydrogenation of a phosphonate substrate analogue by glycerol 3-phosphate dehydrogenase, Biochem.., 141, 729, 1974. 

E. E. Blatter, D. P. Abriola, R. Pietruszko, Aldehyde Dehydrogenase. Covalent Intermediate in Aldehyde Dehydrogenation and Ester Hydrolysis , Biochem. J. 1992, 282, 353-360. 

This is perhaps the most complicated part of the overall process of lignification, for the changes that take place in the monomer units during their polymerization to lignin are no longer of a straightforward biochemical nature. It is now known that the polymerization is initiated by a simple enzymatic phenolic dehydrogenation that leads to a vast variety of complicated chemical structures. 

Glutamate dehydrogenation is involved in deamination of most of the amino acids. The first two reactions are not involved in the overall deamination system they are included here for completeness and because they are of some general interest. The complete biochemical description of these reactions is given in Appendix 8.4. For a few amino acids, e.g. threonine and serine, other specific reactions are responsible for deamination. 

The second function, and the one pertinent to this section, is the decarboxylation of oxalosuccinic acid to 2-oxoglutaric acid. This is simply a biochemical example of the ready decarboxylation of a P-ketoacid, involving an intramolecular hydrogen-bonded system. This reaction could occur chemically without an enzyme, but it is known that isocitric acid, the product of the dehydrogenation, is still bound to the enzyme isocitrate dehydrogenase when decarboxylation occurs. 

Flatanaka T, Kawahara T, Asahi N, Tsuji M (1995) Effects of the structure of poly(vinyl alcohol) on the dehydrogenation reaction by poly(vinyl alcohol) dehydrogenase from Pseudomonas sp. 113P3 T. Biosci Biotechnol Biochem 59 1229-1231... 

Few examples of photochemical dehydrogenation reactions accompanied by cyclization are reported in the literature. 2,3,5-Triphenyl-tetrazolium chloride (CV), which is used biochemically as reduction indicator, on irradiation in ethanol with ultraviolet light, undergoes dehydrogenation accompanied by cyclization to yield 2,3 (2,2 -bi-phenylene)-5-phenyltetrazolium chloride (CVI).106 167 Light-induced cyclization of substituted derivatives of CV to the corresponding bi-phenylene derivatives has been reported recently. sl 33... 

Similar dehydrogenations are often accomplished biochemically. On treatment with Corynebacterium simplex, 19-nortestosterone is transformed into estradiol [1056], Many adrenocortical hormones are converted... 

Several biochemical oxidations can be applied to the conversions of secondary alcohols into ketones. In a complex system containing horse liver alcohol dehydrogenase, ( )-trans-3-methylcyclohexanol and ( )-cis-2-methylcyclopentanol are dehydrogenated to (-)-(5)-3-methylcyclohex-anone (yield 50% ee 100%) and to (+ )-(5)-2-methylcyclopentanone (yield 55% ee 96%), respectively [1036]. 

Oxidations of steroidal keto alcohols to diketones are frequently accomplished biochemically. In addition, isomerization of double bonds, dehydrogenations, and hydroxylations often take place. 

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