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Biomedical subjects

H Tsuzuki

Publications and source records attributed to H Tsuzuki.

At least 91 records · Page 5Linked to original sources
PubMed1981

Effects of proteases on the structure and activity of Pseudomonas aeruginosa exotoxin A.

The effects of various proteases on the enzymatic or biological activity and structure of exotoxin A from Pseudomonas aeruginosa were systematically studied. The toxin was extremely resistant to treatment with various enzymes. The lethality of the toxin disappeared upon treatment with P. aeruginosa protease and elastase, thermolysin, and trypsin with a long incubation time (5h) in the presence of a high enzyme concentration (molar concentration of enzyme to toxin, 1:10 or 1:20), but was little altered by either alpha-chymotrypsin or subtilisin. The decrease of adenosine diphosphate ribosylation activity was moderate when the same treatment was used, regardless to the protease source, except in the case of papain, which was tested in the presence of reducing agents. The increase in activation of the treated toxin determined in the presence of a denaturant and a reducing agent was less than that of the intact toxin, except in the case of trypsin. The differences in disc and sodium dodecyl sulfate gel electropherograms of the toxins treated with these proteases, except for those treated with papain, suggested that the toxins had been nicked by the protease, which resulted in their degradation by sodium dodecyl sulfate treatment. Papain degraded the toxin into fragments and caused the disappearance of lethality or a marked decrease of adenosine diphosphate ribosylation activity.

ADP Ribose Transferases↗
PubMed1981

Comparison of the effects of a multi-component vaccine and a formalin-killed cell vaccine on protection against enzootic of hemorrhagic pneumonia due to Pseudomonas aeruginosa in mink.

Effectiveness of a multi-component vaccine consisting of the common antigen (OEP) derived from Pseudomonas aeruginosa strain N 10 (serotype E) and toxoids of protease and elastase was compared with that of formalin-killed cells of strain N 10 on protection against enzootic of hemorrhagic pneumonia due to P. aeruginosa in mink. One administration of the multi-component vaccine (100 microgram each of OEP, protease toxoid and elastase toxoid) clearly prevented enzootic of hemorrhagic pneumonia due to P. aeruginosa (serotype G) in mink, while a vaccination of formalin-killed cells was much less effective in preventing an epidemic. The difference in mortality rates between two vaccines was remarkable.

Animals↗
PubMed1980

Coupling between Cbz-Arg-OH and Leu-X catalyzed by trypsin and papain.

Trypsin [EC 3.4.21.4] and papain [EC 3.4.22.2] catalyzed the coupling between Cbz-Arg-OH and Leu-X (X=-NH2, -OEt, -OBut, or -NH) in solution. The optimum pH for synthesis by trypsin and by papain was 6.5-7.0 and 5.5, respectively. Papain possessed reactivity several times higher than that of trypsin. To shift the reaction toward synthesis, the concentration of amine components must be at least several times higher than that of the carboxyl component (Cbz-Arg-OH). The effect of the concentration of Leu-X depended upon the nature of X; higher concentrations were required in the following order: -NH2 > -OEt, -OBut > -NH. High concentrations of organic cosolvents were also significant for promoting the synthesis.

Arginine↗
PubMed1979

Protease and elastase of Pseudomonas aeruginosa: inactivation of human plasma alpha 1-proteinase inhibitor.

The present study indicates that crystalline elastase of Pseudomonas aeruginosa is a very potent inactivator of human plasma alpha 1-proteinase inhibitor, the enzyme (E) inactivated the inhibitor (I) almost completely within 1 h at 25 degrees C at a molar ratio of E/I = 1:100. The crystalline P. aeruginosa protease also inactivated the inhibitor, but 100-fold less. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the alpha 1-proteinase inhibitor inactivated by the elastase and protease showed decreases in molecular weight of approximately 5,000 and 10,000, respectively. Regeneration of trypsin was negligible even when bovine trypsin-alpha 1-proteinase inhibitor complex (E/I = 1.0) was treated with the elastase. The affinity of alpha 1-proteinase inhibitor to trypsin was much higher than that to elastase. It was suggested that, assuming the pseudomonal proteases are produced and can inactivate alpha 1-proteinase inhibitor in vivo during pseudomonal diseases, the loss of alpha 1-proteinase inhibitor activity may permit the endogenous serine proteases to cause tissue destruction.

Humans↗