Studies on the Mechanism of Hydrogen Transport in Animal Tissues

Abstract

Earlier in this series of investigations, it was pointed out that succinic dehydrogenase and cytochrome oxidase are associated with the particulate components of cytoplasm (1), and attention was called to the similarity between these particles and the mitochondria which Bensley (2) separated from broken cell preparations by centrifugal means. Szent-Gy~rgyi (3) as well as Stern (4) had previously called attention to the fact that these enzymes are apparently attached to some macromolecular entity. The enzyme which we have called "coenzyme I-cytochrome c reductase" (5) is also in this category (5, 6), and Kabat (7) has shown that alkaline phosphatase is associated with the particulate matter.During this same period, Claude (8) has been perfecting the method of separation of the morphological components of cytoplasm by centrifugal techniques and has obtained discrete granules of material having "the general constitution of a phospholipid-r~onucleoprotein complex" with diameters ranging from 50 to 150 m#. The particles were considered to pre-exist in the original material and were shown to be similar in size and chemical composition to the particles of the Rous tumor virus.These independent observations provide no proof, however, that the enzyme systems include a ribonucleoprotein, since the particulate components might consist of a mixture of ribonucleoprotein particles and enzyme particles. Furthermore, there is thus far no evidence that any given particle contains more than one enzyme (9). Isolation of the enzymes in crystalline form does not provide an answer to the question since it seems likely that the highly active enzymes which have been isolated as soluble proteins of low molecular weight may not occur as such in the cell, but rather (4,7) that they are attached to the larger particles which Claude has shown to contain ribonucleic acid and phospholipid.Kunitz (10) has recently isolated ribonuclease in crystalline form and has demonstrated that it splits r~onucleie acid into smaller acidic groups without

Effects of Sodium Chloride, Phosphate, and Dextrose on the Heat Stability of Purified Myoglobin, Hemoglobin, and Cytochrome c

“…Chlorohemin is not soluble in aqueous condition in the pH 6.3 range, and apomyoglobin would be destabilized more easily than intact Mb. Only -CN, -N3, -NO, and -F can make a complex with cytochrome c by attacking the ironmethionine bond under certain conditions (Potter, 1940;George et al, 1967). Unlike in Mb, salt significantly (P<.01) increased the heat stability of cytochrome c when the temperature was 80 C or higher (Table 3).…”

Interactions of cytochromec with phospholipid membranes

“…Complete reduction of cytochrome c is obtained with an amount of 18" As mentioned in the introduction to this paper, Tsou (1952) had qualitatively distinguished between isolated soluble cytochrome c and the endogenous cytochrome c of a particulate preparation derived from mitochondria on the basis that the endogenous ferricytochrome c did not form a complex with cyanide. Although the shift in the e-peak region (Potter, 1941) at 540 to 530 nm cannot be readily discerned because of interference from light scattering, a shift of the Soret peak from 410 to 413.5 nm, characteristic of the cyanide complex (Tsou, 1952), can be observed. 4 shows the absolute spectrum, obtained as described for Fig.…”

Metabolism of Pipecolic Acid in a Pseudomonas Species IV. Electron Transport Particle of Pseudomonas putida

“…The incomplete reduction of the c-type cvtochrome together with the slight shift in the maxima of the peaks observed when P2-ETP was reduced with pipecolate plus KCN suggest the formation of a cytochrome c-cyanide complex, irreducible by substrate (15,28). If the type c cytochrome of P2-ETP were the component reacting directly with oxygen, the formation of such a complex would explain the stimulatory effect of KCN when the oxidation of different substrates, with DCPIP or mammalian cytochrome c as electron acceptors, was measured.…”