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Biomedical subjects

H Sinohara

Publications and source records attributed to H Sinohara.

At least 73 records · Page 4Linked to original sources
PubMed1985

Murinoglobulin, a novel protease inhibitor from murine plasma. Isolation, characterization, and comparison with murine alpha-macroglobulin and human alpha-2-macroglobulin.

Two glycoproteins having trypsin-protein esterase activity were purified to apparent homogeneity from murine plasma. One was alpha-macroglobulin, a homologue of human alpha-2-macroglobulin, while the other, tentatively named murinoglobulin, did not correspond to any of the known plasma protease inhibitors that have been well characterized in men or other mammals. Murinoglobulin contained about 7.6% carbohydrate and was composed of a single-polypeptide chain of Mr = 180,000 as judged by the equilibrium sedimentation analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Murinoglobulin did not cross-react immunologically with mouse alpha-macroglobulin nor with human alpha-2-macroglobulin. Protease-inhibiting properties of murinoglobulin were compared with those of mouse alpha-macroglobulin and human alpha-2-macroglobulin. All the three proteins inhibited trypsin, papain, and thermolysin, although they differed considerably in both the degree of inhibition and the binding stoichiometry of protease-inhibitor complexes. The two macroglobulins inhibited pepsin at pH 5.5, whereas murinoglobulin was inactivated at this pH. Murinoglobulin was more sensitive to methylamine than the two macroglobulins. No protein corresponding to murinoglobulin was detected in human plasma.

Animals↗
PubMed1985

Isolation and characterization of influenza C virus inhibitor in rat serum.

Two hemagglutination inhibitors for influenza C virus were isolated from pooled sera of normal rats by sequential chromatography on Blue Sepharose CL 6B, Ultrogel AcA 22, and DEAE-cellulose. The two inhibitors were identified as alpha 1-macroglobulin and murinoglobulin by comparison with the authentic samples. These inhibitors abolished the hemagglutination by influenza C virus strains but did not affect the hemagglutination by influenza A and B virus strains. Hemagglutination inhibition activity of both inhibitors was completely destroyed by incubation with influenza C virus at 37 degrees C but not with the other types of influenza virus, indicating that the inhibitors are specific for influenza C virus. The inhibitory activity was also destroyed by incubation with neuraminidase from Arthrobacter ureafaciens. By contrast, no activity was lost after treatment with neuraminidase from Vibrio cholerae. These results suggest that the sialic acid residue(s) which is cleavable by the former neuraminidase but not by the latter is essential for the hemagglutination inhibition. The two inhibitors were inactivated by treating with sodium hydroxide and methylamine but not with sodium metaperiodate.

Animals↗
PubMed1985

Isolation and characterization of influenza C virus inhibitors in rat serum.

Two inhibitors against haemagglutination by influenza C virus were isolated from pooled sera of normal rats by sequential chromatography on Blue Sepharose CL 6B, Ultrogel AcA 2, and DEAE-cellulose. The two inhibitors were identified as alpha 1-macroglobulin and murinoglobulin by comparison with the authentic samples. These inhibitors abolished the haemagglutination by influenza C virus strains but did not affect the haemagglutination by influenza A and B virus strains. Haemagglutination inhibition activity of both inhibitors was completely destroyed by incubation with neuraminidase from Arthrobacter ureafaciens. By contrast, no activity was lost after treatment with neuraminidase from Vibrio cholerae. These results suggest that the sialic acid residue(s) which is excised by the former neuraminidase but not by the latter is essential for the haemagglutination inhibition. The two inhibitors were inactivated by treating with sodium hydroxide and methylamine but not with sodium metaperiodate.

Animals↗
PubMed1985

Rat plasma murinoglobulin: isolation, characterization, and comparison with rat alpha-1- and alpha-2-macroglobulins.

Murinoglobulin, a newly identified mouse plasma protein with trypsin-protein esterase activity (Saito, A. & Sinohara, H. (1985) J. Biol. Chem. 260, 775-781), was also found in rat plasma and purified to apparent homogeneity. The serum level of rat murinoglobulin was 14.1 mg/ml, amounting to 1/3 of the total serum globulin fraction. Rat murinoglobulin was a monomeric glycoprotein (Mr = 210,000) containing 12% carbohydrate. Rat plasma contained two isoforms of murinoglobulin, termed I and II, which showed complete immunological identity on double diffusion analysis using rabbit antiserum raised against isoform I or II. These antisera also showed partial cross-reactivity towards mouse murinoglobulin and rat alpha-1-macroglobulin but not towards rat or human alpha-2-macroglobulin. The chemical compositions, peptide mapping patterns and electrophoretic mobilities of the two isoforms resembled each other but clearly differed from those of rat alpha-1- or alpha-2-macroglobulin. Rat murinoglobulin inhibited the proteolytic activity of trypsin towards casein and remazol brilliant blue hide powder. The inhibition as to the latter substrate was greater than that as to the former. When molar ratios of inhibitor to trypsin were low, murinoglobulin and the two alpha-macroglobulins stimulated the amidolytic activity of trypsin towards a synthetic substrate. At higher ratios, however, murinoglobulin, but not the alpha-macroglobulins, inhibited the same activity. The trypsin-protein esterase activity of murinoglobulin and the two alpha-macroglobulins was impaired by a molar excess of soybean trypsin inhibitor. Murinoglobulin and the two alpha-macroglobulins were inactivated by methylamine with a concomitant unmasking of the thiol group. Murinoglobulin was much more sensitive to soybean trypsin inhibitor and methylamine than the two alpha-macroglobulins.

Amino Acids↗
PubMed1985

Concentrations of murinoglobulin and alpha-macroglobulin in the mouse serum: variations with age, sex, strain, and experimental inflammation.

Serum levels of murinoglobulin and alpha-macroglobulin were low in newborn mice but increased during the prepubertal development. The adult levels of the two inhibitors were higher in males than in females in 8 inbred strains tested. Gonadectomy at 2 w of age did not significantly affect the prepubertal rise in the levels not only of the above two inhibitors but of contrapsin and alpha-1-antiprotease. The gonadectomy, however, abolished the sex differences seen in the adult levels of these inhibitors. The levels of murinoglobulin and alpha-macroglobulin reached their minimum at 12 h after inducing inflammation and returned to normal at 24 h. Little change was observed in the levels of contrapsin and alpha-1-antiprotease under the same inflammatory conditions.

Age Factors↗
PubMed1984

Subunit structure of sex-steroid-binding plasma proteins from man, cattle, dog, and rabbit.

Sex-steroid-binding plasma proteins (SBPs) of man, cattle, dog, and rabbit were purified to apparent homogeneity by sequential chromatography on testosterone-17 alpha-ethynylcarboxyaminoethyl Sepharose and hydroxyapatite. When subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, all the purified SBPs were resolved into two subunits, the relative amounts of which differed considerably from species to species. Two-dimensional electrophoresis according to O'Farrell also revealed that each subunit was further separable into several charged variants. The heavy subunit had somewhat more acidic molecular variants than the light subunit. One molecule of 5 alpha-dihydrotestosterone was bound per dimer of the subunits. Dissociation constants of heavy and light homodimers of rabbit SBP were 3.3 and 4.9 nM, respectively. Polypeptide fragmentation patterns resulting from digestion of heavy and light subunits with protease V8 differed from species to species but resembled each other in each species. These results suggest that the native SBPs may exist as a homodimer of a single variant or a hybrid dimer composed of various combinations of light and heavy variants.

Animals↗
PubMed1984

Variation with age in the levels of sex-steroid-binding plasma protein as determined by radioimmunoassay.

A radioimmunoassay for human sex-steroid-binding plasma protein (SBP) was developed. With this assay, SBP was determined in sera of 138 normal men and 169 non-pregnant women, ranging in age from 11 to 87 years. The results indicate that SBP levels in both sexes increase gradually with age up to mid-eighties, that the average levels in mid-eighties are approximately twice those in early twenties, and that the average levels in women are about twice as high as those in men of corresponding age. These results may also account for the discrepancies in the previous papers regarding the normal blood levels and sexual difference of SBP in adult men and women.

Adolescent↗
PubMed1984

Conformational differences between mouse contrapsin and alpha-1-antitrypsin as studied by ultraviolet absorption and circular dichroism spectroscopy.

We have compared the conformation of mouse contrapsin , a novel trypsin inhibitor ( Takahara , H. and Sinohara , H. (1982) J. biol. Chem., 257, 2438-2446), and alpha-1-antitrypsin by UV absorption and CD spectroscopy. The two mouse inhibitors share a similar secondary structure, i.e., 24-29% alpha-helix, 31% beta-sheet, and 10-11% beta-turn. The corresponding values for human alpha-1-antitrypsin are 48, 25, and 9%, respectively. These results suggest that peptide backbone structures of the two mouse inhibitors resemble each other, but differ slightly from that of human alpha-1-antitrypsin. On the other hand, evidence is accumulated that the microenvironments of aromatic side chains are considerably different in mouse contrapsin and alpha-1-antitrypsin: (i) An unusual fine vibrational structure was seen in the UV absorption spectra of murine and human alpha-1- antitrypsins , but not in that of contrapsin . (ii) CD bands in contrapsin which may be assigned to phenylalanyl residues were several-fold greater in intensity than those in the two alpha-1- antitrypins . (iii) The above-mentioned bands in contrapsin were more susceptible to pH changes than those in alpha-1-antitrypsin. (iv) CD bands in contrapsin which may contain unresolved contributions from tyrosyl and tryptophanyl residues also markedly differed from those in the two alpha-1- antitrypsins . These differences were, however, largely diminished in the presence of 50 mM sodium dodecyl sulfate, suggesting that mouse contrapsin and alpha-1-antitrypsin have a similar structure in the presence of this perturbant .

Animals↗
PubMed1983

Inhibitory spectrum of mouse contrapsin and alpha-1-antitrypsin against mouse serine proteases.

Contrapsin and alpha-1-antitrypsin have been recently characterized as major protease inhibitors in mouse plasma (Takahara, H. & Sinohara, H. (1982) J. Biol. Chem. 257, 2438-2446). We have studied the effects of the two inhibitors upon various serine proteases prepared from mouse tissues. Trypsin, plasmin and trypsin-like proteases of the submaxillary gland were inhibited by contrapsin but not by alpha-1-antitrypsin. On the other hand, chymotrypsin, elastase, and thrombin were inactivated by alpha-1-antitrypsin but not by contrapsin. Thus, their inhibitory spectra did not overlap each other in spite of their broad specificities. The inhibition of trypsin, chymotrypsin, and elastase was rapid and stoichiometric, whereas the inhibition of the other proteases was relatively slow. Contrapsin accounted for almost the total capacities of mouse plasma to inhibit both trypsin and submaxillary gland trypsin-like proteases, whereas alpha-1-antitrypsin was responsible for nearly all the capacities of plasma to inhibit both chymotrypsin and elastase.

Animals↗
PubMed1983

Comparative studies on the serum levels of alpha-1-antitrypsin and alpha-macroglobulin in several mammals.

The sera of human, cattle, horse, sheep, goat, pig, dog, rabbit, guinea pig, rat, hamster, and mouse were assayed for total trypsin-inhibiting capacity, and for concentrations of alpha-1-antitrypsin and alpha-macroglobulin. The rodents examined showed striking species differences: the alpha-1-antitrypsin levels of mouse, rat, and guinea pig were more than twice the human level, while the alpha-macroglobulin levels of hamster and guinea pig were 340 and 40%, respectively, of the human level. On the other hand, little variations were found among the large domestic animals, their levels of the two inhibitors being similar to those of the human.

Animals↗
PubMed1982

Mouse plasma trypsin inhibitors: inhibitory spectrum of contrapsin and alpha-1-antitrypsin.

We have studied the effects of murine alpha-1-antitrypsin and contrapsin, a new trypsin inhibitor (Takahara, H. and Sinohara, H. (1982) J. Biol. Chem. 257, in press), on several serine proteases participating in blood clotting, fibrinolysis, kinin generation, and complement activation. Bovine plasmin and human plasma kallikrein were inactivated by contrapsin but not by alpha-1-antitrypsin, whereas bovine alpha-thrombin and porcine pancreas kallikrein were inhibited by alpha-1-antitrypsin but not by contrapsin. Heparin protected thrombin from inactivation by alpha-1-antitrypsin. Both inhibitors had virtually no effects on canine C1 esterase.

Animals↗
PubMed1982

Mouse plasma trypsin inhibitors. Isolation and characterization of alpha-1-antitrypsin and contrapsin, a novel trypsin inhibitor.

The trypsin-inhibiting capacity of male adult mouse plasma was several-fold greater than that of the corresponding human plasma. Two major trypsin inhibitors were isolated from mouse plasma in an apparently homogeneous state. One seems to be homologous to alpha-1-antitrypsin isolated from several mammalian species, while the other, tentatively named contrapsin, does not correspond to any of the known plasma protease inhibitors that have been well characterized in human or other animals. When human plasma was fractionated in exactly the same fashion, no inhibitor corresponding to contrapsin was detected, suggesting the absence of this inhibitor in human plasma. No cross-reactivity was observed either between contrapsin and antiserum specific for alpha-1-antitrypsin or between alpha-1-antitrypsin and antiserum specific for contrapsin. alpha-1-Antitrypsin inhibited three serine proteases tested, i.e. porcine elastase, bovine trypsin, and chymotrypsin, whereas contrapsin inhibited only trypsin, but not the other two. The two inhibitors, however, shared a number of other properties in common. They were monomeric glycoproteins having total carbohydrate content of 9.6% in alpha-1-antitrypsin (Mr = 53,000) and 15.1% in contrapsin (Mr = 55,000). They had similar amino acid and carbohydrate compositions. They inhibited bovine beta-trypsin by forming stable complexes. They showed similar sex differences in blood concentrations. Serum levels of alpha-1-antitrypsin and contrapsin in males were 5.2 +/- 0.6 and 2.8 +/- 0.2 mg/ml, respectively, whereas those in females were 3.5 +/- 0.2 and 2.1 +/- 0.4 mg/ml, respectively.

Amino Acids↗
PubMed1981

Plasma testosterone-binding proteins in the developing rat.

Blood plasma of male rats aged 3 weeks contained two testosterone-binding proteins which differed in apparent molecular weight on Sephadex G-200 column. The binding characteristics of both proteins were similar. They had high affinity for androgens, but little or no affinity for estrogens and corticoids. Blood concentrations of both proteins began to increase markedly 15 days after birth, reached a peak at about 20 days, and then decreased. The higher molecular weight form disappeared by 5 weeks of age, whereas the lower molecular weight form was reduced to much lower levels that remained relatively unchanged until the end of the experimental period, i.e., 63 days of age.

Age Factors↗
PubMed1981

Isolation and characterization of sex-steroid-binding protein from rat and rabbit plasma.

The sex-steroid-binding plasma protein (SBP), which had been reported to be absent in the rat by several workers, was detected in 6-week-old male rats, but not in female rats aged 5-43 days. The rat SBP was purified to apparent homogeneity by affinity chromatography on testosterone-17-alpha-ethynylcarboxyaminoethyl Sepharose 4B followed by hydroxyapatite column chromatography, and its properties were compared with those of rabbit SBP prepared in exactly the same fashion. The concentration of SBP in adult male rabbit was 25-fold greater than that in 6-week-old male rat, but the binding characteristics of both SBPs were very similar. They specifically bind testosterone, 5 alpha-dihydrotestosterone, and 5 alpha-androstane-3 alpha, 17 beta-diol, but have virtually no affinity for estradiol, progesterone, or cortisol. Equilibrium dissociation constants for dihydrotestosterone were estimated to be 11.7 nM for rat SBP and 14.9 nM for rabbit SBP.

Aging↗