Hikokichi Oura

Rat serum ribonuclease

Abstract Rat serum ribonuclease has been purified about 6000-fold. The optimal pH of this enzyme was 7–8. The purified enzyme was rather heat labile at pH 7.6. The Km of this enzyme is 30% higher than that of the crystalline bovine pancreatic ribonuclease (polyribonucleotide 2-oligonucleotide-transferase, EC 2.7.7.16). No stimulatory or inhibitory effect on this enzyme was observed with EDTA, KCl, MgCl2. p-chloromercuribenzoinc acid, or mercaptoethanol.

Adaptive response of tryptophan pyrrolase and tyrosine transaminase in rat liver after partial hepatectomy and laparotomy

Abstract Tryptophan pyrrolase ( L -tryptophan: H 2 O 2 oxidoreductase, EC 1.11.1.4) and tyrosine-α-ketoglutarate transaminase ( L -tyrosine: 2-oxoglutarate amino transferase, EC 2.6.1.5) activities of rat liver homogenate were increased about 2–2.5 fold in 4–6 h after laparotomy, and 4–6 fold in 8–10 h after partial hepatectomy, without loading of gluccorticoid or substrate. The rise of tryptophan pyrrolase was inhibited by actinomycin D administered immediately after operation. In adrenalectomized rats, the induced tryptophan pyrrolase activity was inhibited. The increased activity in tryptophan pyrrolase after partial hepatectomy has been attributed to change in supernatant fraction, and was not affected by administration of cortisone.

Polyribosomes in antibody-forming tissues of hyperimmunized rabbits

Abstract 1. 1. Lymph nodes of hyperimmunized rabbits have been found to contain polyribosomes which are dissociated into monomers by ribonuclease. 2. 2. By means of an enzyme-antienzyme system, specific inhibition of bacterial α-amylase activity with these ribosomal fractions has been observed.