NADP-specific isocitrate dehydrogenase of Mycobacterium phlei ATCC 354: purification and characterization.
NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42) from Mycobacterium phlei ATCC 354 was purified to homogeneity by ammonium sulphate fractionation, followed by DEAE cellulose and Sephadex G-200 chromatography. The pH optimum of the enzyme was 8.5. The Km values for isocitrate and NADP were 74 and 53 microM, respectively. Mn2+ was essential for enzyme activity. The enzyme lost all activity on incubation at 70 degrees C for 15 min; isocitrate and NADP protected against this thermal inactivation. p-Chloromercuribenzoate inhibited the enzyme; pre-incubation of enzyme with isocitrate + Mn2+ prevented this inhibition. The purified enzyme showed concerted inhibition by glyoxylate + oxaloacetate and was inhibited by oxalomalate.
Dhariwal
K R
KR
Department of Biochemistry, University of Delhi, India.
Venkitasubramanian
T A
TA
D006038:Glyoxylates / Q000494:pharmacology; D007521:Isocitrate Dehydrogenase / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D009161:Mycobacterium / Q000201:enzymology*; D009168:Mycobacterium phlei / Q000201:enzymology*; D010071:Oxaloacetates / Q000494:pharmacology
D006038:Glyoxylates; D010071:Oxaloacetates; D007521:Isocitrate Dehydrogenase; C039355:isocitrate dehydrogenase (NADP+); C031150:glyoxylic acid