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Biomedical subjects

K Morihara

Publications and source records attributed to K Morihara.

At least 73 records · Page 4Linked to original sources
PubMed1977

alpha-Chymotrypsin as the catalyst for peptide synthesis.

alpha-Chymotrypsin (EC 3.4.21.1)-catalysed syntheses of peptides were performed with various N-acylated amino acid or peptide esters as donors, and amino acid derivatives, peptides or their derivatives as acceptors. Under optimal conditions the synthesis was almost quantitative. As acceptor nucleophiles, free amino acids or the ester derivatives were inadequate, but amino acid amides or hydrazides, di- or tri-peptides, or the amides, hydrazides and esters of the peptides were useful. The nucleophile specificity for synthesis was markedly similar to the leaving-group specificity in hydrolysis; hydrophobic or bulky amino acid residues were most effecient at both P1' and P2' positions [notation of Schechter & Berger (1967) Biochem. Biophys. Res. Commun. 27, 157-162], but L-proline as well as D-amino acid residues were the worst choices. The synthesis was further dependent on the solubility of the products synthesized; a higher yield of products was expected with lower solubility. As donor esters, good substrates were all useful. Accordingly, fragment condensation was possible by using N-acylated peptide esters and various peptides. The present study suggested that alpha-chymotrypsin may become a useful tool for peptide synthesis.

Amino Acids↗
PubMed1977

Trypsin as a catalyst for peptide synthesis.

Trypsin-catalyzed syntheses of peptides were performed using various N-acylated amino acid or peptide esters as donors and amino acid derivatives, peptides, or their derivatives as acceptors. The synthesis was almost quantitative under optimal conditions. Considerably more enzyme and a more alkaline pH were necessary for synthesis than hydrolysis. Another very important condition was the concentration of the starting materials; higher concentrations resulted in much better product yields. The nucleophile specificity for synthesis was also important; hydrophobic or bulky amino acid residues were most efficient at the P1' position, and L-proline as well as D-amino acid residues were the worst choices. The synthesis was also dependent on the solubility of the products synthesized; the yield was higher with products of lower solubility. As donor esters, good substrates were all useful. Accordingly, fragment condensation was possible using N-acylated peptide esters and various peptides. The present study suggests that trypsin may become a useful tool for peptide synthesis.

Animals↗
PubMed1977

Production of protease and elastase by Pseudomonas aeruginosa strains isolated from patients.

Using 20 strains of Pseudomonas aeruginosa isolated from patients, production of protease, elastase, and collagenase was determined by shaking culture in either complex or semisynthetic medium. No collagenase was produced by any strain of P. aeruginosa. According to their production of protease and elastase in different media, the P. aeruginosa strains were divided into three groups: the first group can produce elastase in complex medium and both protease and elastase in semisynthetic medium; the second group cannot produce any proteolytic enzymes in complex medium but can produce any proteolytic enzymes in either medium; and the third group cannot produce any proteolytic enzymes in either medium. In spite of the differences in the ability of the strains to produce the enzymes, depending upon the origin of the strains, the protease or elastases produced in different broths were regarded as identical.

Caseins↗
PubMed1975

Effects of protease and elastase from Pseudomonas aeruginosa on skin.

Protease and elastase were inoculated intracutaneously in rabbits, the process of which was followed. Of the enzymes, 50 mug caused circumscribed hemorrhage at the inoculated local and subcutaneous part, and ulcerating lesions of skin and extensive hemorrhagic lesion at the subcutaneous tissues were observed in the case of inoculation with 250 mug. The doses amounting to 500 to 1000 mug of the enzymes caused extensively ulcerating, necrotic lesions at the skin and extensive hemorrhage at the subcutaneous tissue, and a large amount of hemorrhage was observed in the abdomen. It was observed microscopically that cellular infiltration and hemorrhage in the subcutaneous tissue and muscular layer were caused by administration of 2 to 10 mug of the enzymes, and that degeneration of endothelial cells was caused by 2 mug of them.

Animals↗
PubMed1975

In vivo studies on protease and elastase from Pseudomonas aeruginosa.

Protease and elastase from Pseudomonas aeruginosa were inoculated in female mice by intravenous, intraperitoneal, intrapleural and intranasal route, and the lethality and damage of various organs were examined. The protease and elastase exhibited respectively the following minimum lethal dose (MLD) values in 24 hr; 300 and 375 mug inoculated intravenously; 200 and 125-250 mug intraperitoneally; and 100 and 62.5 mug intrapleurally. The instillation of a defined dose of the enzyme by the intranasal route was difficult to control, therefore the MLD could not be defined exactly. The protease and elastase were capable of eliciting hemorrhage at various organs of mice according to the route of inoculation. Of protease, intravenous injections elicited petechial hemorrhage at the lungs and parietal bone-area, and severe one in the medullary area of kidney. The intraperitoneal injection resulted in petechial hemorrhage of the lungs, diaphragm, peritoneum and gastrointestinal serosa. Intrapleural injections and intranasal instillation resulted in confluent pulmonary hemorrhage. Of elastase, intravenous injections elicited confluent pulmonary hemorrhage, hemorrhage in the medullary area of kidney and cerebral ventricles, and petechial hemorrhage at the stomach-walls. The intraperitoneal injections resulted in petechial hemorrhage at the lungs, diaphragm, peritoneum and gastointestinal serosa. Intrapleural injections resulted in confluent pulmonary hemorrhage, and petechiae at the diaphragm and pleura. Intranasal instillation resulted in confluent pulmonary hemorrhage.

Animals↗