Origin of p-aminobenzoic acid from chorismic rather than iso-chorismic acid in Enterobacter aerogenes and Streptomyces species.
Enzyme extracts from Enterobacter aerogenes (62-1), Streptomyces aminophilus, and Streptomyces coelicolor were used to investigate the biosynthesis of p-aminobenzoic acid. The enzyme preparations from E. aerogenes and S. aminophilus contained both p-aminobenzoate synthase and iso-chorismate synthase activity, and were able to convert both chorismic and iso-chorismic acid to p-aminobenzoic acid. The apparent KM for chorismic acid was, however, significantly lower than that for iso-chorismic acid, while the Vmax was identical for both substrates in both enzyme systems. The enzyme preparations from S. coelicolor did not contain iso-chorismate synthase activity and p-aminobenzoic acid synthesis took place in this system from chorismic acid only. It is concluded that iso-chorismic acid is not an obligatory intermediate in p-aminobenzoic acid biosynthesis in these organisms.
Johanni
M
M
Institut für Pharmazeutische Biologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Federal Republic of Germany.
Hofmann
P
P
Leistner
E
E
D010129:4-Aminobenzoic Acid / Q000378:metabolism*; D062365:Aminobenzoates / Q000378:metabolism*; D002827:Chorismic Acid / Q000378:metabolism*; D003509:Cyclohexanecarboxylic Acids / Q000378:metabolism*; D053138:Cyclohexenes; D004754:Enterobacter / Q000201:enzymology*; D004755:Enterobacteriaceae / Q000201:enzymology*; D007536:Isomerism; D007700:Kinetics; D008190:Lyases / Q000378:metabolism; D019761:Phosphorus-Oxygen Lyases; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity; D000637:Transaminases / Q000378:metabolism
D062365:Aminobenzoates; D003509:Cyclohexanecarboxylic Acids; D053138:Cyclohexenes; C052985:isochorismic acid; C022309:PABA synthase; D000637:Transaminases; D008190:Lyases; C019895:chorismate synthase; D019761:Phosphorus-Oxygen Lyases; D002827:Chorismic Acid; D010129:4-Aminobenzoic Acid