Pyruvoyl-dependent histidine decarboxylases from Clostridium perfringens and Lactobacillus buchneri. Comparative structures and properties.

Histidine decarboxylase (EC 4.1.1.22) was purified to homogeneity from Clostridium perfringens and also from Lactobacillus buchneri. Both enzymes are composed of alpha and beta subunits, with an essential pyruvoyl group bound to the alpha subunit. In this respect and also in molecular weight of both the alpha and beta subunits and the native enzyme, they closely resemble the previously described (Riley, W.D., and Snell, E. E. (1970) Biochemistry 9, 1485-1491) histidine decarboxylase from Lactobacillus 30a. Rabbit antibodies to the latter enzyme cross-react incompletely with the decarboxylase from L. buchneri but not with that from C. perfringens in double diffusion tests. The clostridial decarboxylase differs substantially from the Lactobacillus 30a enzyme in amino acid composition and, unlike the latter enzyme, requires high ionic strength (I approximately 1.4 M) for maximum activity. The enzymes also differ in rates of electrophoretic migration. A proenzyme for the decarboxylase similar to that previously found in Lactobacillus 30a was detected in immunoprecipitates of extracts of L. buchneri. We conclude that these proteins arise from pyruvate-free precursor proteins by similar mechanisms and probably have diverged from a common ancestral protein.