Transformation of N epsilon-CBZ-L-lysine to CBZ-L-oxylysine using L-amino acid oxidase from Providencia alcalifaciens and L-2-hydroxy-isocaproate dehydrogenase from Lactobacillus confusus.

Abstract

Biotransformations were developed to oxidize N epsilon-carbobenzoxy(CBZ)-L-lysine and to reduce the product keto acid to L-CBZ-oxylysine. Lysyl oxidase (L-lysine: O2 oxidoreductase, EC 1.4.3.14) from Trichoderma viride was relatively specific for L-lysine and had very low activity with N epsilon-substituted derivatives. L-Amino acid oxidase (L-amino acid: O2 oxidoreductase [deaminating], EC 1.4.3.2) from Crotalus adamanteus venom had low activity with L-lysine but high activity with N epsilon-formyl-, t-butyoxycarbonyl(BOC)-, acetyl-, trifluoroacetyl-, or CBZ-L-lysine. L-2-Hydroxyisocaproate dehydrogenase (EC 1.1.1.-) from Lactobacillus confusus catalyzed the reduction by NADH of the keto acids from N epsilon-acetyl-, trifluoroacetyl-, formyl- and CBZ-L-lysine but was inactive with the products from oxidation of L-lysine, L-lysine methyl ester, L-lysine ethyl ester or N epsilon-t-BOC-L-lysine. Providencia alcalifaciens (SC9036, ATCC 13159) was a good microbial substitute for the snake venom oxidase and also provided catalase (H2O2:H2O2 oxidoreductase EC 1.11.1.6). N epsilon-CBZ-L-Lysine was converted to CBZ-L-oxylysine in 95% yield with 98.5% optical purity by oxidation using P. alcalifaciens cells followed by reduction of the keto acid using L-2-hydroxyisocaproate dehydrogenase. NADH was regenerated using formate dehydrogenase (formate: NAD oxidoreductase, EC 1.2.1.2) from Candida boidinii. The Providencia oxidase was localized in the particulate fraction and catalase activity was predominantly in the soluble fraction of sonicated cells. The pH optima and kinetic constants were determined for the reactions.