Lysine biocatalytic

L. W. Parker, and J. J. Venit, Biocatalytic preparation of a chiral synthon for a vasopeptidase inhibitor enzymatic conversion of N2-[N-phenylmethoxy)carbo-nyl] L-homocysteinyl]- l-lysine (1,1 J-disulfide to 4S-(4/,71,10aJ)]-l-octahydro-5-oxo-4-[phenylmethoxy)carbonyl]amino]-7H-pyrido-[2,l-b][l,3]thiazepine-7-carboxylic add methyl ester by a novel l -lysine e-aminotransferase, Enzyme Microb. Technd. 2000, 27, 376-389. 

Tethering of photoisomerizable groups to enzymes has been used to photostimu-late the biocatalytic functions of proteins.134,351 Papain was modified by the covalent coupling of the photoisomerizable units trans-4-carboxyazobenzene (7), trans-3-car-boxyazobenzene (8), or trans-2-carboxyazobenzene (9) to the protein s lysine residues (Scheme 4). The new azobenzene-modified papains underwent reversible trans cis... 

L-Lysine is produced on an enormous scale, over 500,000 tons per year, mostly through fermentation using genetically modified organisms. A biocatalytic route was also used to produce L-lysine, the most popular being... 

Figure 6. Electrical wiring of glucose oxidase with ferroeene units tethered to lysine residues of the protein backbone (cf. Figure 5B). (A) Cyelic voltammograms of a bare Au electrode in the presence of modified GOx (10 mg mL ) and glucose at (a) 0, (b) 0.8 and (c) 5 mM. Experiments were performed in 0.085 M phosphate bulfer, pH 7.0, under argon. (B) Glucose concentration dependence of the current at 0.26 V vs. SCE developed by the biocatalytic system (using a larger electrode). Adapted from Ref. [83] with permission.

Although very interesting biotranformations have been reported in supercritical carbon dioxide, this solvent has been found to affect enzyme activity adversely. CO can react reversibly with free amino groups (lysine residues, specifically) on the surface of the protein to form carbamates, leading to low activity enzyme. [21]. Furthermore, carbon dioxide dissolves in water at molar concentrations at moderate pressures (<100 bar) and rapidly forms H COj. This can create some problems in biocatalytic reactions because many enzymes are denatured (unfolded and/or deactivated) at low pH. Enzymes can also be denatured by pressurization/depressuriza-tion cycles. For all of them, it is necessary to develop new enzyme stabilization strategies. 

Cyclic amides can also be hydrolyzed in a highly selective fashion using enzymes. A well known example in this respect is the biocatalytic production of L-lysine from d,l-a-amino- -caprolactam (d,l-ACL) I45"47 . This process is based on the combination of two enzymatic reactions the enzymatic enantiospecific hydrolysis of L-a-amino-s-caprolactam to L-lysine and the simultaneous racemization of the residual D-a-amino-s-caprolactam (Scheme 12.2-10). 

Patel. R.N.. Banerjee.A., Nanduri, V., Goldberg. S.. Johnston. R.. Hanson, R., McNamee, C., Brzozowski. D.. Tully. T.. Ko. R.. LaPorte. T.. Cazzulino, D., Swaminathan, S.. Parker. L.. and Venit. J. (2000) Biocatalytic Preparation of a Chiral Synthon for a Vasopeptidase Inhibitor Enzymatic Conversion of bP- N-[(Phenylmethoxy)carbonyl]L-homocysteinyl]-L-lysine (1>1 )-disulfide to [4B-(4a.7a,10ab)]l-Octahydro-5-oxo-4-[(phenyl-methoxy) carbonyl]amino]-7H-pyrido-[2.1-b][l 3]thiazepin-7-carboxylic Acid Methyl Ester by a Novel S-Lysine a-Amino-transferase. Enzyme Microb. Technol. 27,376-389. 

Photodiromic groups covalently attached to enzymes are, in certain cases, capable of affecting the tertiary protein structure upon light-induced isomerization. As a consequence, the biocatalytic activity of the enzymes can be switched on and off [29]. For example, the catalytic activity of papain is inhibited when 4-carboxy-trans-azobenzene groups covalently linked to the lysine moieties of the enzyme undergo trans-cis isomerization (see Scheme 5.5). At a loading of five units per enzyme molecule, 80% of the catalytic activity is retained. 

Cadaverine (diaminopentane, DAP), a carbon-5 aliphatic metabolite, is a minor member of the biogenic polyamine family. It owes its trivial name to its first discovery in 1885 during systematic investigation of the putrefaction process of human cadavers [52]. In contrast to DAB, there is no efficient petrochemical production route available, which for a long time hampered its industrial application in the polymer industry. However, several bio-based production processes have meanwhile been developed for DAP production from renewable resources [6, 12, 15-17, 53]. Only recently, Cathay introduced the fully biobased polyamide PA5.10 Terryl , which entered the market in 2015. While the proprietary production process relies on biocatalytic conversion of the rather high-priced fine-chemical lysine, other attempts aim at a fully novo biosynthesis with streamlined cell factories for the direct fermentative production of DAP from cheap conventional fermentation feedstock. For establishing a one-step fermentation process for DAP, the industrial lysine producers E. coli and C. glutamicum were therefore the ideal metabolic chassis. 

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