title: Arginine aminopeptidase activity of phytopathogenic spiroplasmas.
abstract: The arginine aminopeptidase activity of arginine-utilizing phytopathogenic spiroplasmas was investigated with arginine beta-naphthylamide substrate using the fluorometric method. Hydrolysis of this substrate was demonstrated with broth cultures, washed concentrated whole cells, and cell-free extracts of corn stunt spiroplasma (CSS) and Spiroplasma citri. Growing CSS and S. citri in the presence of 47 mM arginine resulted in a reduction in aminopeptidase activity, indicating that synthesis of the enzyme might be subject to control by catabolic repression. Results of these experiments suggest a possible biochemical basis for pathogenicity of phytopathogenic spiroplasmas in vivo.
mesh_terms: D000626:Aminopeptidases / Q000096:biosynthesis / Q000378:metabolism*; D001120:Arginine / Q000378:metabolism; D004794:Enzyme Repression; D010944:Plants / Q000382:microbiology; D013149:Spiroplasma / Q000201:enzymology*
chemical_list: D001120:Arginine; D000626:Aminopeptidases; C019721:aminopeptidase B