Nα-Z-L-lysine

The present paper reviews the enzymes catalyzing conversion of Nα-benzyloxycarbonyl-L-lysine (Nα-Z-L-lysine) to Nα-benzyloxycarbonyl-L-aminoadipic acid (Nα-Z-L-AAA) in fungal and bacterial strains. Aspergillus niger AKU 3302 and Rhodococcus sp. AIU Z-35-1 converted Nα-Z-L-lysine to Nα-Z-L-AAA via Nα-benzyloxycarbonyl-L-aminoadipate-δ-semialdehyde (Nα-Z-L-AASA). However, different enzyme combinations were involved in the Nα-Z-L-lysine metabolism of both strains. A. niger strain converted Nα-Z-L-lysine to Nα-Z-L-AASA by amine oxidase, and the resulting Nα-Z-L-AASA was converted to Nα-Z-L-AAA by an aldehyde oxidase. In the Rhodococcus strain, conversion of Nα-Z-L-lysine to Nα-Z-L-AASA was catalyzed by l-specific amino acid oxidase. The resulting Nα-Z-L-AASA was converted to Nα-Z-L-AAA by an aldehyde dehydrogenase. The present paper also describes characteristics of new enzymes obtained from those strains.

Poly(epsilon-caprolactone) (PCL) macromers (M(n) = 1.7-3.8 kDa) which contain one Z-protected -NH2 group per chain were synthesized by ring-opening polymerization of epsilon-caprolactone in the presence of Sn(oct)2 using as initiator a diamine prepared by condensation of N-Boc-1,6-hexanediamine and N(alpha)-Boc-N(epsilon)-Z-L-Lysine. The coupling of these macromers with -COCl end-capped poly(oxyethylene) (PEO), M(n) = 1.0 kDa, afforded amphiphilic multiblock poly(ether ester)s (PEEs) which have, along the chain, regularly spaced pendant protected amino groups. Deprotection, accomplished without chain degradation, yielded -NH2 groups available for further reactions. The molecular structure of macromers and PEEs was investigated by 1H NMR and SEC. DSC and WAXS analyses showed that macromers and copolymers were semicrystalline and their T(m) increased with increase in the molecular weight of PCL segments. The inherent viscosity values (0.25-0.

The enzymes responsible for the conversion of N(alpha)-[(benzyloxy)carbonyl]-D-lysine (N(alpha)-Z-D-lysine) to N(alpha)-Z-D-aminoadipic acid (N(alpha)-Z-D-AAA) by Rhodococcus sp. AIU Z-35-1 were identified. N(alpha)-Z-D-Lysine was first converted to N(alpha)-Z-D-aminoadipic delta-semialdehyde (N(alpha)-Z-D-AASA) by D-specific amino acid deaminase, whereas N(alpha)-Z-L-lysine was converted to N(alpha)-Z-L-AASA by L-specific amino acid oxidase. The resulting N(alpha)-Z-D-AASA was then converted to N(alpha)-Z-D-AAA by the same aldehyde dehydrogenase that is responsible for N(alpha)-Z-L-AASA oxidation. The product amount of the D-specific amino acid deaminase reached the maximum at one day of cultivation in the L-lysine medium. The aldehyde dehydrogenase reached the maximum at three days of cultivation.

An enzyme exhibiting oxidase activity for β-lactoglobulin, myoglobin, and l-lysine-containing peptides was found from a newly isolated fungal strain, Penicillium steckii AIU 027. The enzyme also oxidized l-amino acids, N(α)-benzyloxycarbonyl-l-lysine (N(α)-Z-l-lysine) and N(ε)-Z-l-lysine, but not d-amino acids and amines. Thus, the enzyme was classified into a group of l-amino acid oxidases (l-AAOs). However, characteristics of this l-AAO were significantly different from those of other l-AAOs as follows. The l-AAO from P. steckii AIU 027 oxidized both the α-amino group and the ε-amino group in l-amino acids and l-lysine-containing peptides, and the Km values for l-lysine-containing polypeptides were lower than those for N(α)-Z-l-lysine and l-lysine-containing dipeptides. The enzyme contained flavin and iron, and composed of four identical subunits with molecular mass of 75.3 kDa. The N-terminal amino acid sequence, ENIADVADAMGPWFDGVAYMKSKKN, was different from that of other l-AAOs.