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Biomedical subjects

Y Inada

Publications and source records attributed to Y Inada.

At least 289 records · Page 16Linked to original sources
PubMed1985

Ester synthesis at extraordinarily low temperature of -3 degrees C by modified lipase in benzene.

The lipoprotein lipase from Pseudomonas fluorescens was modified with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine. The modified lipase in which 55% of the amino groups in the enzyme molecule were coupled with polyethylene glycol was found to be soluble in benzene and catalyzed the reactions of ester synthesis, ester exchange, aminolysis and ester hydrolysis in benzene. The modified lipase had an extraordinary temperature-dependency: enzymic activity for methyl laurate synthesis from methyl alcohol and lauric acid increased with decreasing temperature and attained the maximum at the extremely low temperature of -3 degrees C. The optimum temperature for hydrolysis of methyl laurate was as low as -4 degrees C.

Benzene↗
PubMed1984

Polyethylene glycol-modified catalase exhibits unexpectedly high activity in benzene.

Bovine liver catalase with molecular weight of 248,000, which consists of four subunits, was modified with 2,4-bis(o-methoxypolyethylene glycol)-6-chloro-s-triazine(activated PEG2). The modified catalase became soluble in organic solvents such as benzene by increasing the degree of modification of amino groups in the enzyme with activated PEG2. The enzymic activity of the modified catalase in benzene, in which 42% of the total amino groups were coupled with the modifier, was unexpectedly high in comparison with the activity of non-modified catalase in aqueous system. The absorption spectrum of the modified catalase in benzene showed the characteristic pattern of a haem protein with Soret band at 405 nm. The temperature-activity profile of the modified catalase in benzene was clarified and its activation energy was estimated to be 1900 cal/mol.

Animals↗
PubMed1984

Chymotrypsin modified with polyethylene glycol catalyzes peptide synthesis reaction in benzene.

Chymotrypsin was modified in the zymogen form with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine (activated PEG2), followed by activation with trypsin. The modified enzyme was soluble in benzene and retained its enzymic activity. Acid-amide bond formation by the modified enzyme proceeded efficiently in benzene: N-benzoyltyrosine butylamide was made from N-benzoyl-L-tyrosine ethyl ester and n-butylamine, and benzoyltyrosine(oligo)phenylalanine ethyl esters were formed from N-benzoyl-L-tyrosine ethyl ester and L-phenylalanine ethyl ester.

Animals↗
PubMed1984

Successive study on the production of plasminogen activator in cultured endothelial cells by phytosterol.

In a previous study(1), it was demonstrated that one of phytosterols, sitosterol, has an ability to increase the intracellular and extracellular activities of plasminogen activator in cultured endothelial cells and that other steroids including cholesterol, 5-androsten-3 beta-ol, stigmasterol, 20(R)-propyl-5-pregnen-3 beta-ol and 20(R)-heptyl-5-pregnen-3 beta-ol have no ability. Once-stimulated cells went back to normal states by removal of sitosterol. The similar lines of research for plasminogen activators were reported by several groups which were cited in a previous paper(l). In the present communication, we found that fucosterol, which is present mainly in brown algae, Phaeophyta, enhances the production of plasminogen activator in endothelial cells, as well as sitosterol. A similar enhancement was not observed for other steroids and sex hormones including androsterone, testosterone, estrone and estradiol. Synthesis of plasminogen activator induced with fucosterol or sitosterol was inhibited by protein synthesis inhibitor, cycloheximide. The plasminogen activators produced in cells were, in the present study, classified into urokinase-type activators with molecular weights of 31,000 and 55,000 and tissue-type ones with molecular weights of 81,000 and 130,000, which were identified with respective antibodies. The synthesis of each type of plasminogen activator in endothelial cells was stimulated by sitosterol or by fucosterol.

Animals↗
PubMed1984

Agonist-specific desensitization of shape change of platelets.

Using scanning electron microscopy and light scattering we have investigated the shape change of bovine platelets. The extents of shape change obtained by ADP and 5-hydroxytryptamine(5HT) increased in dose-dependent manner, and the maximum obtained by these agonists were additive. The agonist-specific desensitization in shape change was observed with ADP, 5HT and thrombin. The extent of desensitization by pre-exposure to ADP was dependent upon the concentration of ADP. It was strongly indicated that receptors or their subsequent stimuli-transmission apparatus became unable to respond to further stimulation after the exposure to the initial stimulation.

Adenosine Diphosphate↗
PubMed1984

Ester synthesis catalyzed by polyethylene glycol-modified lipase in benzene.

Lipoprotein lipase, which catalyzes hydrolysis of emulsified triglycerides or water-insoluble esters, was modified with 2,4-bis(o-methoxy-polyethylene glycol)-6-chloro-s-triazine(activated PEG2). The modified lipase, in which 55% of the total amino groups in the lipase molecule, was soluble in organic solvents such as benzene, toluene, chloroform and dioxane. The modified lipase could catalyze ester synthesis reaction in benzene. When very hydrophobic substrates of lauryl alcohol and stearic acid were used, the ester synthesis reaction proceeded efficiently in the transparent benzene solution with the maximum activity of approximate 5.0 mumoles/min/mg of protein. Ester exchange and aminolysis reactions were also conducted with the modified lipase in benzene.

Benzene↗
PubMed1984

A chemical modification to make horseradish peroxidase soluble and active in benzene.

Horseradish peroxidase was modified with 2,4-bis(O- methoxypolyethylene glycol)-6-chloro-s-triazine. The modified peroxidase, in which 60% of the amino groups were coupled with polyethylene glycol, had 70% of the enzymic activity in aqueous solution and was found to be soluble in benzene. Since the modified peroxidase in benzene had an absorption spectrum similar to that of unmodified peroxidase in aqueous solution, the prosthetic group, protohaemin IX, remained with the apoprotein even in benzene. The modified peroxidase in benzene had 21% of the enzymic activity relative to that of unmodified enzyme in aqueous solution.

Benzene↗
PubMed1984

Specific desensitization of actin polymerization of bovine platelets.

Polymerization of actin induced by activation of platelets was investigated using deoxyribonuclease I inhibition assay. When platelets were activated with ADP or 5-hydroxytryptamine, actin was polymerized quickly followed by rapid depolymerization to the initial level. Reactivation with the same agonist, however, did not cause the polymerization of actin, though with different agonists actin polymerized quite normally. The mechanism for this agonist-specific desensitization of actin polymerization was investigated by the use of a calcium ionophore A23187. It was suggested that the cause for the desensitization is the inability of platelets to mobilize Ca2+ in response to specific agonist.

Actins↗
PubMed1984

Sitosterol-stimulative production of plasminogen activator in cultured endothelial cells from bovine carotid artery.

The endothelial cell is a rich source of plasminogen activator that is associated with fibrinolytic activity in blood vessel. Addition of sitosterol to the culture medium of endothelial cells from bovine carotid artery gave rise to a marked increment in the activity of plasminogen activator. Removal of sitosterol from the culture medium resulted in a decrease of plasminogen activator activity back to normal levels. Enhancement of plasminogen activator activity in cultured endothelial cells was not observed by cholesterol, 5-androsten-3 beta-ol and others.

Animals↗
PubMed1984

Determination of fragment D-dimer derivatives in serum reactive with antiserum against human fragment D-dimer.

A previous study demonstrated the preparation of an antiserum having enough specificity and sensitivity for a radioimmunoassay to determine fragment D-dimer derivatives. Using the antiserum the contents of fragment D-dimer derivatives in the sera of normal subjects and patients were determined. The content in normal subjects was 0.260 +/- 0.07 micrograms/ml (mean +/- SD) an that in patients with elevated levels of FDP ranged from 0.30 to 28 micrograms/ml. The values of fragment D-dimer derivatives and FDP in sera of some patients did not necessarily change in parallel, although there seems to be generally a positive correlation between them.

Antigen-Antibody Reactions↗