Homocitrate is a component of the iron-molybdenum cofactor of nitrogenase

• Published in: Biochemistry (Easton) Vol. 28; no. 7; pp. 2768 - 2771
• Main Authors: Hoover, Timothy R, Imperial, Juan, Ludden, Paul W, Shah, Vinod K
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04.04.1989
• Subjects: 550201 - Biochemistry- Tracer Techniques; BASIC BIOLOGICAL SCIENCES; BIOSYNTHESIS; CARBOXYLIC ACID SALTS; Chromatography, DEAE-Cellulose; Chromatography, Gel; Chromatography, Ion Exchange; CITRATES; COENZYMES; ENZYMES; Ferredoxins - biosynthesis; HYDROGEN COMPOUNDS; Kinetics; Klebsiella pneumoniae - enzymology; MAGNETIC RESONANCE; Magnetic Resonance Spectroscopy; Molybdoferredoxin - biosynthesis; Molybdoferredoxin - isolation & purification; NITRO-GROUP DEHYDROGENASES; NITROGENASE; Nitrogenase - biosynthesis; Nitrogenase - isolation & purification; NUCLEAR MAGNETIC RESONANCE; OXIDOREDUCTASES; PURIFICATION; RESONANCE; SYNTHESIS; Tricarboxylic Acids - analysis; Tricarboxylic Acids - metabolism; TRITIUM COMPOUNDS; UPTAKE
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00433a004

When apodinitrogenase (lacking FeMo-co) was activated with FeMo-co synthesized in vitro in the presence of 3H-labeled homocitrate, label was incorporated into dinitrogenase. The physical association of the label with FeMo-co was demonstrated by reisolation and purification of the cofactor from dinitrogenase. The presence of homocitrate in FeMo-co was established by NMR analysis of the organic acid extracted from dinitrogenase. Quantitation of homocitrate in dinitrogenase showed it to be present at a 1:1 ratio with molybdenum.