Organization of Krebs tricarboxylic acid cycle enzymes in mitochondria.

Malonate inhibition of oxidations in the Krebs tricarboxylic acid cycle.

The inhibition of succinate oxidation by malonate is a well known phenomenon. Since the oxidation of succinate to fumarate is an integral part of the Krebs cycle of oxidations, it has been generally assumed that the inhibitory effect of malonate upon the oxidation of any member of the cycle is the result of the inhibition of the succinate to fumarate step. However, the present paper provides ev...

Distribution of tricarboxylic acid cycle enzymes and glyoxylate cycle enzymes between mitochondria and peroxisomes in Tetrahymena pyriformis.

Tetrahymena Pyriformis cells were grown axenically, harvested in the stationary phase of the cultures when the organism is glyconeogenetically active, homogenized, and fractionated either by isopycnic density gradient centrifugation in a sucrose gradient or by zonal differential sedimentation through a sucrose gradient. Protein and enzyme determinations carried out on the fractions led to the f...

Intracellular distribution of tricarboxylic acid cycle enzymes in Azotobacter vinelandii.

The cytological complexity of the bacterial cell is well established, but little information is as yet available on the association of metabolic function with cellular structure in microorganisms. The significance of the tricarboxylic acid (TCA) cycle and the electron transport system in the metabolism of the obligate aerobic azotobacter cell makes important a knowledge of the intracellular dis...

Tricarboxylic acid cycle enzymes of the ectomycorrhizal basidiomycete, Suillus bovinus.

In crude cell extracts of the ectomycorrhizal fungus, Suillus bovinus, activities of citrate synthase, aconitase, isocitrate dehydrogenase, succinate dehydrogenase, fumarase, and malate dehydrogenase have been proved and analyzed. Citrate synthase exhibited high affinities for both its substrates: oxaloacetate (Km = 0.018 mM) and acetyl-CoA (Km = 0.014 mM). Aconitase showed better affinity for ...

Tricarboxylic Acid Cycle in