Purification and properties of diaminopimelate decarboxylase of Micrococcus glutamicus.

Diaminopimelate decarboxylase (EC 4.1.1.20) of Micrococcus glutamicus ATCC
13059 was purified to homogeneity. The enzyme had an apparent molecular weight of 191,000
as determined by gel filtration on Sephadex G-200. At protein concentrations of 20 and 10 μg
per ml and in the absence of pyridoxal-5'-phosphate, it dissociated into a species of molecular
weight 94,000. The polypeptide chain molecular weight as determined by sodium dodecyl
sulphate Polyacrylamide gel electrophoresis was 100,000. The Km for meso diaminopimelate
was 0.5 mM and that for pyridoxal-5'-phosphate was 0.6 μΜ. Sulphydryl groups and pyridoxal-
5'-phosphate were essential for activity and stability. The enzyme was inhibited significantly
by L-lysine and DL-aspartic β-semialdehyde.