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Mitochondria can be isolated rapidly from Neurospora crassa with high yields by disruptingThe isolated mitochondria respire with pyruvate + malate, succinate, and with NADH and Three phosphorylation steps are involved in the oxidation of pyruvate and two in the oxidation Rotenone, antimycin and ICCN inhibit the electron flow at the known steps. The cytochrome composition pattern is characterized by a particularly high content of cytochrome c.Evidence is given for the existence of two NADH-dehydrogenases for the oxidation of exogenous and endogenous NADH with different localizations on the inner mitochondria1 membrane.On the basis of these properties, mitochondria from Neurospora crassa can be looked upon in analogy to mitochondria from yeast, particularly from Torulopsis utilis.the hyphae suspension between the two grinding wheels of a simple mill. NADPH in high rates and well coupled to oxidative phosphorylation. of succinate, NADH and NADPH.

Phosphoglycerate kinase, isolated from rabbit muscle in highly purified crystalline form, was compared in terms of chemical, physical and kinetic properties to yeast phosphoglycerate kinase. A summary of the data is presented. Both proteins are composed of a single polypeptide chain, and in electrophoresis only one band was found. The N‐terminus is masked. The C‐terminal amino acid of the muscle enzyme is valine. Muscle and yeast enzyme have nearly identical molecular weights, Michaelis‐Menten constants, optimal pH values and Vmax. On the other hand, they differ significantly in their amino acid composition, especially in the content of sulfur and aromatic amino acids, in electrophoretic mobility and in heat stability. The muscle enzyme has an essential SH group. The single SH group of the yeast enzyme is apparently without importance for enzyme activity. Differences in the same direction as those observed with yeast and muscle phosphoglycerate kinase are discussed in connection with other glycolytic enzymes from the same organisms.

Triose phosphate isomerase was isolated from brewer's yeast and rabbit liver and was obtained in crystalline form. Chemical, physical and kinetic properties were compared to rabbit muscle triose phosphate isomerase. The molecular weight of all three enzymes is in the range of 56000 to 60000. In dodecyl sulfate or as modified maleylated protein, the enzymes dissociate into two polypeptide chains each having a molecular weight in the range of 24000 to 29000. The rabbit muscle and liver enzymes appear to be indistinguishable in terms of their amino acid composition, electrophoretic mobility, kinetic properties, inhibition sensitivity, pH optimum, molecular weight and N‐terminal amino acid (alanine). The yeast enzyme, on the other hand, was found different in the following respects; it has a several fold lower content of sulfur amino acids, is highly resistant to inactivation through photooxidation as well as sulfhydryl and alkylating agents. Furthermore, it contains different N‐terminal amino acids (valine and alanine) and has kinetic properties differing from those of the rabbit enzymes. The crystalline liver and muscle enzymes could be resolved into three distinct electrophoretic forms in starch and polyacrylamide gels. The possible interpretation of the multiple forms in terms of hybrids or conformers is discussed.