Albert Fine

Reversible inhibitions of cytochrome system components by macromolecular polyions

Abstract Cytochrome oxidase activity of whole heart homogenates, Keilin and Hartree heart muscle particles, and deoxycholate-treated heart muscle oxidase preparations were all inhibited by the polycations, protamine (sulfate), histone, ribonuclease, and lysozyme. The polycationic inhibitions could be blocked and reversed by the polyanions, polyglucose sulfate, polyethylene sulfonate, carageenins, sulfochitosans, DNA, chondroitin sulfate, and heparin. Neither hyaluronic acid nor n-acetylneuraminic were effective in regard to blocking or reversing the polycation inhibitions of oxidase activity. Polyglucose sulfate and other macroanions, alone, were capable of increasing the cytochrome oxidase activity of non-protamine-treated enzyme preparations. Polyglucose sulfate also restored oxidase activity lost as a result of aging of enzyme preparations. Polyanionic substances including polyglucose sulfate, chondroitin sulfate, heparin and glutamyl polypeptides formed complexes with cytochrome c, with resultant loss in catalytic activity of the hemeprotein. Such complex formation could be reversed by addition of protamine to the system, with reactivation of cytochrome c. The reversible interactions between polyions and the cytochrome system components were more effective in Tris than in phosphate buffers of equal molarities. Increase in ionic strength beyond 0.08, resulted in a weakening of the protamine inhibition of oxidase activity. It was concluded that coulombic attractions between cytochrome system components and oppositely charged polyions were involved in the phenomena described.

BASIC BIOLOGICAL SCIENCES Confirmation that Neither Phenotype Nor Hydroxylation of Collagen Is Altered In Overgrown Gingiva From Diphenylhydantoin-Treated Patients

Collagens, solubilized by pepsin-digestion of diphenylhydantoin-induced overgrown gingiva, appeared similar to collagens solubilized from inflamed gingiva with regard to: ratio of type I to type III collagen, ratio of α1 to α2 of type I collagen, and degree of hydroxylation of type I collagen.

Cytochrome oxidase and succinoxidase activity of Limulus gill cartilage

It has been shown that homogenates of gill cartilage prepared from young (2–3 in. long) specimens of Limulus polyphemus, the horseshoe crab, are capable of oxidizing reduced cytochrome c. This activity is inhibited by 10−4 M cyanide and azide. This marks the first demonstration of cytochrome oxidase activity in cartilage from any source. Such homogenates in the presence of added cytochrome c also mediate hydroquinone oxidation via cytochrome oxidase. QO2 values between 6 and 10 were obtained. Oxygen uptake was also inhibited by 10−4 M cyanide and azide. The presence of malonate-sensitive succinic dehydrogenase and a succinoxidase complex in the gill cartilage homogenates was established.

ON THE PRESENCE OF MYOGLOBIN AND CYTOCHROME OXIDASE IN THE CARTILAGINOUS ODONTOPHORE OF THE MARINE SNAIL, BUSYCON

1. Myoglobin and cytochrome oxidase activities were shown to exist together in a cartilaginous tissue for the first time, in the odontophore of Busycon canaliculatum.2. The absorption spectra of the cartilage myoglobin were characteristic for this class of pigments. Similarly, the absorption spectra of the pyridine hemochrome prepared from the pigment were characteristic of ferroprotoporphyrin-pyridine hemochrome.3. The Qo2 (dry weight basis) of cartilage homogenates, employing hydroquinone as substrate and added cytochrome c, was 9.4 in an air atmosphere at 37° C. Such homogenates were also capable of oxidizing reduced cytochrome c.

Biochemical and Histochemical Studies of Aerobic Oxidative Metabolism of Oral Tissues. III. Specific Metabolic Activities of Enzymatically Separated Gingival Epithelium and Connective-Tissue Components:

In a preceding paper, we have described separations of human and dog gingiva, and of rat tongue, epithelia, from their respective connective tissues, using a variety of enzymes and also thiocyanate compounds.1 The present report deals with specific oxidative enzyme activities of separated dog gingival epithelium and connective-tissue components and with preliminary studies of enzymatically treated human gingival preparations. In addition to determining specific enzymatic activities of the separated tissue components, we wanted to know whether or not the data obtained would support or refute a hypothesis put forth by us in paper I of this series, namely, that gingival tissues contain endogenous substances which act as inhibitors of aerobic oxidative enzyme systems.2

MEDIATION OF p-AMINODIPHENYLAMINE OXIDATION VIA CYTOCHROME OXIDASE

Manometric studies have revealed that the oxidation of p-aminodiphenylamine by Keilin and Hartree beef heart muscle particles was several-fold higher in the presence of added cytochrome c than in the absence of the pigment. The oxidation of p-aminodiphenylamine was inhibited 90% by 10–4 M cyanide. Correlated spectrophotometric studies demonstrated that the oxidation of p-aminodiphenylamine by Keilin and Hartree particles and fresh-frozen dehydrated tissue sections produced substances with identical visible and ultraviolet absorption spectra. The above experiments further indicate that the oxidation of p-aminodiphenylamine is mediated via cytochrome oxidase, and that this reagent provides valid histochemical localizations of the respiratory enzyme.