Citrate synthase from human heart was purified by affinity chromatography with Sepharose-ATP. The molecular weight (100 000) and presence of two presumably identical subunits do not differ from other mammalian citrate synthases. However, the kinetic constants, and immunologic characteristics of the enzyme, differed from findings from other mammalian citrate synthases. The Km values for acetyl CoA (0.4 μm) and oxaloacetate (0.25 μm) were about an order of magnitude lower than that previously found for other mammalian (and eucaryotic) citrate synthases. The kinetic constants for the reverse reaction, Km for citrate (420 μm) and CoA (70 μm) were of similar magnitude to the values for other mammals. Anti-human heart antiserum developed a single precipitin line in an Ouchterlony plate against a heart extract, no precipitin line with brain, and a precipitin line with spurs against liver and kidney extract. Following myocardial infarction in men, the enzyme appeared in peripheral blood rarely and in low concentration in contrast with earlier experiences with experimental infarction in dogs.
- Citrate synthase
- Myocardial infarction
ASJC Scopus subject areas
- Molecular Biology
- Cardiology and Cardiovascular Medicine