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Biomedical subjects

M Irie

Publications and source records attributed to M Irie.

At least 217 records · Page 12Linked to original sources
PubMed1986

Kinetic studies on turtle pancreatic ribonuclease: a comparative study of the base specificities of the B2 and P0 sites of bovine pancreatic ribonuclease A and turtle pancreatic ribonuclease.

Kinetic constants for the transesterification of eight dinucleoside phosphates CpX and UpX by bovine and turtle pancreatic ribonuclease were determined. Both ribonucleases have a preference for purine nucleotides at the position X. However, bovine ribonuclease, like other mammalian ribonucleases, prefers 6-amino bases at this site, while turtle ribonuclease prefers 6-keto bases. This difference in specificity at the B2 site may be explained by the substitution of glutamic acid at position 111 by valine in turtle ribonuclease. These results have been confirmed by inhibition studies with the four nucleoside triphosphates. Inhibition studies with pT and pTp showed that a cationic binding group (P0) for the 5'-phosphate of the pyrimidine nucleotides bound at the primary B1 site is present in turtle ribonuclease, although lysine at position 66 in bovine ribonuclease is absent in turtle ribonuclease. However, the side chain of lysine 122 in turtle ribonuclease is probably located in the correct position to take over the role as cationic P0 site.

Animals↗
PubMed1986

Comparison of the antigenicities of native human growth hormone (hGH) and three forms of recombinant hGHs using monoclonal antibodies.

A panel of hybridomas producing antibodies specific for human growth hormone (hGH) were prepared by using a recombinant hGH [methionylsomatotropin (r-hGH)] as an immunogen. Thirteen representative monoclonal antibodies which showed different reactivity patterns were used to analyze the antigenicities of four different forms of hGHs by RIA inhibition studies. Native hGH and r-hGH showed almost the same antigenicities with these monoclonal antibodies. A Cys-substituted recombinant hGH (r-hGH-165) retained the epitopes recognized by 11 monoclonals but not those recognized by two monoclonals. All except one of the monoclonals showed little or no reactivity with a recombinant hGH fragment (r-hGH-AB). On the basis of these results, the differences in the structures and antigenicities of the recombinant hGH proteins were discussed.

Animals↗
PubMed1986

Roles of lysine1 and lysine7 residues of bovine pancreatic ribonuclease in the enzymatic activity.

In order to investigate the roles of Lys1 and Lys7 of RNase A in the enzymatic activity, four S-peptide derivatives were prepared and their abilities to activate S-protein were measured. They are 1-norleucine-S-peptide, 7-norleucine S-peptide, 1,7-di-norleucine-S-peptide, and tri-N-acetyl S-peptide. From the analyses of the relative activity and kinetic parameters of RNase S' derivatives with UpU, UpU greater than p, and UpUpU greater than p, it was concluded that Lys7 of RNase A is a binding site for 3'-phosphate of UpU greater than p and the modification or substitution of Lys1 affects the binding of trinucleotide substrate.

Animals↗
PubMed1986

Distribution of two urinary ribonuclease-like enzymes in human organs and body fluids.

In order to determine the distribution of two human urinary RNase (RNase Us and RNase UL)-like enzymes in human tissues and body fluids, enzyme immunoassay systems were established using rabbit anti-RNase sera. The sensitivity of the assay systems was of similar order to that of radioimmunoassay systems previously reported. In the enzyme immunoassay, the cross reactivities of anti-RNase UL serum towards RNase Us, bovine kidney RNase K2, bovine RNase A, and bovine seminal RNase Vs were less than 1%. The cross reactivity of anti-RNase Us-serum towards RNase UL was less than 0.5% and cross reactivities were minimal for RNase A, RNase K2, and RNase Vs. The RNase levels in human organs and body fluids were measured by enzyme immunoassay. In milk, semen and saliva, only RNase UL-like enzyme was found. Both RNase Us- and RNase UL-like enzymes were found in kidney, stomach, and pancreas and the RNase Us/RNase UL ratios were 0.49, 1.35, and 0.34, respectively. In lung, liver, spleen, and leukocytes, most of the RNase activity was accounted for by RNase Us-like enzyme. The activity of RNase Us-like enzyme was especially high in lung, spleen, and leukocytes. The crude extracts of several tissues and body fluids were separated by phosphocellulose column chromatography and the contents of the two urinary RNase-like enzymes were determined by enzyme immunoassay. In stomach, kidney, pancreas, and serum, both enzymes were present in multiple forms. In spleen and lung, both the major RNase (RNase Us) and minor RNase (RNase UL) existed in two forms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Site of alkylation of the major ribonuclease from Aspergillus saitoi with iodoacetate.

A base non-specific and adenylic acid preferential ribonuclease from Aspergillus saitoi (RNase M) was modified by [14C]iodoacetic acid. RNase M was inactivated with concomitant incorporation of about 1 mol equivalent of carboxymethyl group. Carboxymethylated RNase M (CM RNase M) thus obtained was reduced and carboxymethylated (RCM CM RNase M). From tryptic and chymotryptic digests of RCM CM RNase M, two carboxymethylated histidine-containing peptides labeled with radioactivity were isolated. The amino acid sequences of these two peptides were determined to be Thr-Ile-His-Gly-Leu-Trp-Pro-Asp-Asn-Cys-Asp-Gly-Ser-Tyr... and His-Gly-Thr-Cys-Ile-Asn-Thr-Ile-Asp-Pro-Ser-Cys-Tyr-Pro-Asp-Asp-Tyr-Ala. .... The distribution of the radioactivity on the former and latter peptides was 43% and 57%, respectively. The results indicated that two histidine residues are involved in the active site of RNase M, and the modification of either one of the two histidine residues inactivates RNase M. The CD spectrum of carboxymethylated RNase M indicated that some tryptophan residue(s) with a CD band at 287 nm is in the proximity of the active site histidine residues of RNase M.

Alkylation↗
PubMed1986

Pharmacokinetic properties of testosterone propionate in normal men.

The pharmacokinetic characteristics of testosterone propionate were studied in normal men after a single im dose of 25 mg testosterone propionate-19,19,19-d3. Plasma levels of testosterone propionate-19,19,19-d3, its active metabolite testosterone-19,19,19-d3, and endogenous testosterone were measured by gas chromatography-mass spectrometry. Testosterone propionate-19,19,19-d3 was gradually transferred from the im injection site to the systemic circulation. The plasma levels of testosterone propionate-19,19,19-d3 were maintained at 2-4 ng/ml between 3 and 36 h after administration. Plasma testosterone-19,19,19-d3 levels were maintained above the physiological testosterone level for 48 h, while plasma levels of endogenous testosterone changed little.

Adult↗
PubMed1986

Treatment of pituitary dwarfism with methionyl human growth hormone in Japan.

Sixty-two patients with pituitary dwarfism were treated with three different preparations of methionyl hGH (m-hGH) for 3 to 14 months. They were given 0.5 IU/kg/week intramuscularly. The growth rate during treatment with the three different preparations was the same for each and increased from 3.5 +/- 0.9 to 8.2 +/- 1.7 cm/year. A high incidence of hGH antibody formation was observed following the treatment, but the titer of antibody was decreased according to the purity of m-hGH preparations. At the end of 12 month treatment with a highly purified preparation (Somatonorm III), 76.2% of the patients had hGH antibody. However, the presence of antibodies did not affect the growth rate except in one patient. No clinical or laboratory side-effects were observed following the treatment with m-hGH. Thus, m-hGH was considered to be useful for the treatment of GH deficient children.

Adolescent↗
PubMed1986

[Obstetric factors associated with intracranial hemorrhage (ICH) in premature infants and antenatal prediction of ICH].

Obstetric factors associated with intracranial hemorrhage (ICH) were evaluated in 98 inborn premature infants of less than 1,500 gm birth weight or less than 32 weeks of gestation. ICH was detected in 25 (25.5%) of these infants by ultrasound sonography and/or computed tomography. No association of obstetric factors such as maternal age, parity, gravidity, premature rupture of the membrane, toxemia, placenta previa, fetal position, mode of delivery or fetal sex with ICH was noted. But the ICH group showed a higher incidence of placental abruption, infarction, infection and incompetent cervix than the non-ICH group. In addition, gestational ages and birth weights were less in the ICH group than in the non-ICH group, although differences were not significant except for the group with incompetent cervix (p less than 0.05). However, Apgar scores and FHR scores according to Krebs et al. for the ICH group were significantly lower than those for the non-ICH group. The two groups were distinguished by multivariable discriminant analysis of FHR scores, birth weights and gestational ages (discriminant efficiency, 3.74: F-value, 20.6: true positive ratio, 81.3%). These results suggested that antenatal prediction of ICH in premature infants was possible, but further studies are needed to elucidate the reliability of its prediction.

Adult↗
PubMed1985

Identification and characterization of a variant of the third component of complement (C3) in rainbow trout (Salmo gairdneri) serum.

A rainbow trout serum protein that is cross-reactive with the third complement component of rainbow trout (C3-1) was purified to homogeneity and its structural and functional properties compared with those of C3-1. This protein (termed C3-related protein: C3-2) bears a close structural resemblance to C3-1, although C3-2 apparently shows no hemolytic activity. Like C3-1, C3-2 consists of two disulfide-linked polypeptide chains (128,000 alpha and 72,000 beta) and retains the unique thiol ester site in the alpha-chain. C3-2 shares some antigenicity with C3-1, but it also displays distinctive antigenic determinants of its own. Comparison of tryptic peptide maps revealed that about 20% of the peptides was specific to either C3-1 or C3-2, and about 80% of the peptides were common to both proteins. Amino acid compositions of the alpha- and beta-chains of C3-2 were similar to those of C3-1. Furthermore, amino acid sequence analysis of the NH2 termini of the alpha- and beta-chains of C3-2 revealed a high degree of homology with those of C3-1, 24 of 26 residues in the alpha-chain and all 20 in the beta-chain of C3-2 were identical with those found in C3-1. Both C3-1 and C3-2 were detected in all the adult rainbow trout tested and in first generation offspring randomly bred from them.

Alleles↗
PubMed1985

Modification of a minor glucoamylase from Aspergillus saitoi with 1-cyclohexyl-3-(2-morpholinyl-(4)-ethyl)carbodiimide metho p-toluenesulfonate.

In order to elucidate the structure-function relationship of glucoamylases [EC 3.2.1.3, alpha-D-(1-4)-glucan glucohydrolase] from Aspergillus saitoi, the reaction of a minor component, Gluc M2 with 1-cyclohexyl-3-(2-morpholinyl-(4)-ethyl)carbodiimide metho p-toluenesulfonate (CMC) was studied at pH 4.5. Inactivation of Gluc M2 with [14C]CMC proceeded with the incorporation of about 5 CMC moieties. From the results of analyses of amino acid and sulfhydryl contents of CMC-modified Gluc M2 and the hydroxylamine treatment of the CMC-modified Gluc M2 at pH 7.0, it was concluded that the sites of CMC-modification were carboxylic acids of Gluc M2. In the presence of maltose, when Gluc M2 was treated with [14C]CMC, ca. 4 CMC moieties were incorporated with a simultaneous decrease in activity (30%). The Gluc M2 modified in the presence of maltose was re-modified with CMC after elimination of maltose. The CMC-modified Gluc M2 (70% activity) was inactivated completely with the further incorporation of ca. 2 CMC moieties. The logarithm of the half-life of the inactivation of Gluc M2 by CMC was a linear function of log[CMC] indicating that one carboxyl group among the modified ones was crucial for the inactivation of Gluc M2. From the results of these modification reactions, it was concluded that one or two carboxylic acids in Gluc M2 were crucial for the catalysis of glucoamylase from A. saitoi. Based on the analysis of the pH-profile of CMC inactivation of Gluc M2, the participation of a carboxylic acid having pKa 5.7 in the active site is proposed.

Amino Acids↗
PubMed1985

Purification and properties of bovine kidney ribonucleases.

Two RNases (RNases K1 and K2) were purified from bovine kidney by means of column chromatography on phospho-cellulose, Sephadex G-50, CM-cellulose, heparin-Sepharose, nd agarose-APUP. They were named RNase K1 and RNase K2 in order of elution from the heparin-Sepharose column. The purity of RNase K1 thus obtained was about 90% by SDS-disc electrophoresis. RNase K2 was purified to homogeneity by SDS- and pH 4.3 disc electrophoresis. The yield of RNase K2 was 3.4 mg from 11 kg of kidneys. The antigenic properties of the two bovine renal RNases were studied by Ouchterlony's double diffusion analysis. RNase K1 and RNase A were serologically indistinguishable. RNase K2 did not cross-react immunologically with RNase K1 or RNase A. The molecular weights of these RNases determined by gel-filtration on Sephadex G-50 were 13,400 and 14,600 for RNase K1 and RNase K2, respectively. The pH optima for RNase K1 and RNase K2 were 8.5 and 6.5, respectively. Both RNase K1 and RNase K2 were as acid stable as RNase A. RNase K2 was less heat-stable than RNase K1 and RNase A. Although both renal RNases were pyrimidine nucleotide-specific enzymes, RNase K1 and RNase A were more preferential or cytidylic acid than RNase K2. The chemical composition of RNase K2 was determined. RNase K2, like human urinary RNase Us, contained one tryptophan residue. The N-terminal sequences of RNase K2 and RNase Us were determined by Edman degradation. Rnase K2 had a homologous sequence of about 10 amino acid residues with the sequence of RNase Us, a typical non-secretory RNase, within the N-terminal 30 residues.

Amino Acids↗
PubMed1985

Modification of a ribonuclease from Rhizopus sp. with 1-cyclohexyl-3-(2-morpholinyl-(4)-ethyl)carbodiimide p-toluenesulfonate.

The carboxyl group in a ribonuclease from Rhizopus sp. (RNase Rh) was modified by a water-soluble carbodiimide, 1-cyclohexyl-3-(2-morpholinyl-(4)-ethyl)carbodiimide p-toluenesulfonate (CMC). From the relation between the extent of modification and the enzymatic activity, it was concluded that at least the modification of two carboxyl groups seemed to induce the loss in enzymatic activity. In the presence of 1 M cytidine, RNase Rh activity was protected from the CMC-modification. Under conditions in which the enzyme was inactivated to 20% activity, about 70% of the enzymatic activity was retained in the presence of cytidine. The inactivation of the RNase Rh pre-treated with CMC in the presence of cytidine with [14C]CMC indicated that the RNase Rh lost its enzymatic activity with the incorporation of about one [14C]CMC. Therefore, it could be concluded that one carboxyl group is involved in the active site of RNase Rh. The binding of the CMC-modified RNase Rh with 2'-AMP was studied spectrophotometrically. The affinity of the modified RNase Rh towards 2'-AMP decreased markedly upon CMC modification.

Adenosine Monophosphate↗
PubMed1985

Inhibition of glucoamylases from a Rhizopus sp. and Aspergillus saitoi by aminoalcohol derivatives.

The mechanism of inhibition of the two glucoamylases from a Rhizopus sp. and Aspergillus saitoi by aminoalcohol derivatives was investigated. Hydrolysis of maltose by the glucoamylases was inhibited competitively by aminoalcohols at pH 5.0, and tris(hydroxymethyl)aminomethane, 2-amino-2-ethyl-1,3-propanediol and 2-aminocyclohexanol were relatively good inhibitors of the glucoamylases among the aminoalcohol derivatives tested. One hydroxyl group and an amino group in these inhibitors were indispensable for the inhibitory action, and the addition of other hydroxyl, amino or ethyl groups was enhancing. With an increase in pH from 4.0 to 6.0, the Ki values of the aminoalcohols decreased. This result suggested the participation of a carboxyl group, which was related to the glucoamylase activity and had a pKa of 5.7, in the binding of aminoalcohols. The UV difference spectra induced on binding of the aminoalcohol analogues with the glucoamylases may indicate a change of the environment of tryptophan residues to a slightly higher pH on inhibitor binding. The influence of aminoalcohols on the fluorescence intensity due to tryptophan residues and the CD-spectra of the glucoamylases was less than that of maltitol. Thus, the interaction of aminoalcohols with tryptophan residues in the glucoamylases might be less pronounced than that in the case of substrate analogues. The modes of binding of the aminoalcohols with the two glucoamylases were very similar. Therefore, the phenomenon might be a common feature of glucoamylases in general.

Amino Alcohols↗