ISSN:
1572-9699
Schlagwort(e):
lysine biosynthesis
;
aspartate-derived amino acids
;
oxaloacetate decarboxylase
;
pyruvate kinase
;
Corynebacterium glutamicum
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract Oxaloacetate (OAA) decarboxylase (E.C. 4.1.1.3) was isolated fromCorynebacterium glutamicum. In five steps the enzyme was purified 300-fold to apparent homogeneity. The molecular mass estimated by gel filtration was 118 ± 6 kDa. SDS-PAGE showed a single subunit of 31.7 KDa, indicating an α4 subunit structure for the native enzyme. The enzyme catalyzed the decarboxylation of OAA to pyruvate and CO2, but no other α-ketoacids were used as substrate. The cation Mn2+ was required for full activity, but could be substituted by Mg2+, Co2+, Ni2+ and Ca2+. Monovalent ions like Na+, K+ or NH 4 + were not required for activity. The enzyme was inhibited by Cu2+, Zn2+, ADP, coenzyme A and succinate. Avidin did not inhibit the enzyme activity, indicating that biotin is not involved in decarboxylation of OAA. Analysis of the kinetic properties revealed a K m for OAA of 2.1 mM and a K m of 1.2 mM for Mn2+. The V max was 158 µmol of OAA converted per min per mg of protein, which corresponds to an apparent k cat of 311 s−1.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00871217
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