The Oxidation Systems of Mitochondrial Particles from Aspergillus Oryzae*

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Abstract
From the homogenate of the cells with 1M sucrose, containing 0.01[image] MgCl2 and 0.1[image] Tris (trishydroxymethyl aminomethane) buffer (pH 7.5), P1(nuclei), P2(mitochondria), P3(microparticle), and S(sol.) fractions were prepared by differential centrifugations, at 500,10,000, and 20,000 x g, respectively P2,P3 and S were active towards DPNH(reduced diphosphopyridine nucleotide) and the substrates of tricarboxylic acid cycle in presence of cytochrome c or 2,6-dichlorophenolindophenol. Pyruvate was oxidized by P2 only by the presence of the latter compound and rather accelerated by KCN. The Fe2+ inhibition of P2 and P3 for the DPNH oxidation and counteraction by the appropriate amount of KCN or EDTA (ethylenediamine tetra-acetate) suggest that some metal ions bound to mitochondrial particles may maintain a low level of DPNH oxidation. But an excess amount of KCN or EDTA rather lessens reactivation against Fe2+. Enzyme activity of P2 in situ is discussed in relation to its structure.