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Biomedical subjects

M Moroi

Publications and source records attributed to M Moroi.

71 records · Page 4Linked to original sources
PubMed1978

Effects of alpha2-plasmin inhibitor on fibrin clot lysis. Its comparison with alpha2-macroglobulin.

The major plasmin inhibitors namely alpha2-plasmin inhibitor and alpha2-macroglobulin were compared for their effects on lysis of fibrin clot. Plasmin fibrinolytic activity was immediately inhibited by alpha2-plasmin inhibitor, whereas alpha2-macroglobulin inhibited plasmin progressively. Urokinase(plasminogen activator)-induced clot lysis was inhibited efficiently by alpha2-plasmin inhibitor present in the clot. Inhibition of urokinase-induced clot lysis by alpha2-macroglobulin was weak and the molar concentration necessary for alpha2-macroglobulin to achieve the same degree of inhibition as that achieved with alpha2-plasmin inhibitor was about 10 times higher than that of alpha2-plasmin inhibitor. Binding of Lys-plasminogen to fibrin was inhibited by alpha2-plasmin inhibitor but not by alpha2-macroglobulin. Molar concentrations of alpha2-plasmin inhibitor which were effective in inhibiting the binding were 30 times less than that of 6-aminohexanoicacid. alpha2-Plasmin inhibitor was found to interact with Lys-plasminogen to form a weakly-bound complex which is dissociable in the presence of 6-aminohexanoic acid, suggesting that inhibition of binding of Lys-plasminogen to fibrin by alpha2-plasmin inhibitor may be due to interaction of alpha2-plasmin inhibitor with a specific site of the plasminogen molecule and that the site may be 6-aminohexanoic acid-binding site. It is suggested that alpha2-plasmin inhibitor is more reactive and efficient inhibitor of fibrinolysis than alpha 2-macroglobulin.

Aminocaproic Acid↗
PubMed1978

Abnormal plasminogen. A hereditary molecular abnormality found in a patient with recurrent thrombosis.

A patient who suffered a recurring thrombosis over the last 15 yr has been investigated. The only abnormality found in this patient was a significantly depressed level of plasminogen activity in plasma. In spite of the depressed plasminogen activity, the patient was found to have a normal level of plasminogen antigen concentration. It was calculated that the activity per milligram of plasminogen of the patient was approximately one-half the values of normal subjects. The same discrepancy between biological activity and antigen concentration was found in the other members of the kindred. A niece was found to have practically no plasminogen activity but possessed a normal concentration of plasminogen antigen. Both her parents were found to have approximately half the normal plasminogen activity and normal antigen levels. These studies suggested that the molecular abnormality was inherited as an autosomal characteristic, and the family members who had half the normal levels of activity with normal plasminogen antigen were heterozygotes whereas the one with practically no plasminogen activity was homozygote. Subsequent studies showed that the pattern of gel electrofocusing of purified plasminogen of the heterozygotes consisted of 10 normal bands and 10 additional abnormal bands, each of which had a slightly higher isoelectric point than each corresponding normal component. This indicates that plasminogen of the heterozygote is a mixture of normal and abnormal molecules in an approximately equal amount, which was substantiated by active site titration of purified plasminogen preparations obtained from the propositus and a normal individual. The gel electrofocusing pattern of the homozygote consisted of abnormal bands only. The defect is a hereditary abnormality of plasminogen.

Adult↗
PubMed1977

On the interaction of alpha2-plasmin inhibitor and proteases. Evidence for the formation of a covalent crosslinkage and non-covalent weak bondings between the inhibitor and proteases.

alpha2-plasmin inhibitor is a proteinase inhibitor in plasma which efficiently inhibits the lysis of fibrin clots induced by plasminogen activator. The nature of the binding of the inhibitor to trypsin or plasmin was studied by the chemical treatment of the enzyme-inhibitor complex with 7.5 M hydrazine at pH 10.0. With the hydrazine treatment, the complexes were degraded to proteins corresponding to the respective enzyme and inhibitor moieties. These results indicate that the covalent bond between the inhibitor and the enzymes is a carboxylic ester. The binding reaction of the inhibitor to active site-modified trypsin was also studied. The inhibitor formed complexes with anhydrotrypsin and carboxyamidomethylated trypsin. The complexes were dissociated in the presence of 1% sodium dodecyl sulfate, to the individual components: the respective enzyme and inhibitor moieties. The inhibitor, however, did not form a complex with diisopropylphosphorylated trypsin regardless of the presence or absence of the denaturing reagent. These results suggest the contribution of non-covalent interactions to the complex formation between the inhibitor and native enzymes.

Binding Sites↗
PubMed1977

Inhibition of proteases in coagulation, kinin-forming and complement systems by alpha2-plasmin inhibitor.

Inhibitory activities of alpha2-plasmin inhibitor against various proteases were investigated. The inhibitor promptly inhibited the esterolytic activity of alpha-chymotrypsin and progressively inhibited the esterolytic or amidolytic activities of bovine plasma kallikrein, bovine thrombin and bovine activated factor X. Heparin had no effect on the reaction of the inhibitor with thrombin or activated factor X. However, the inhibitor had no effect on the activities of human C-1-esterase, papain and snake venom kininogenase. On the basis of its rapid inhibition of kallikrein, alpha2-plasmin inhibitor is considered to exert some regulating effect on kallikrein activity in plasma.

Animals↗
PubMed1977

The behavior of alpha2-plasmin inhibitor in fibrinolytic states.

Human plasma alpha2-plasmin inhibitor in fibrinolytic states was studied using immunochemical methods and radioiodinated plasminogen. The concentration and activity of plasma alpha2-plasmin inhibitor decreased when urokinase was added to plasma in vitro or infused intravenously in man. The decrease was associated with the appearance of plasmin-alpha2-plasmin inhibitor complex which subsequently disappeared from the circulation in a short time. A decrease of other major inhibitors, such as alpha2-macroglobulin and alpha1-antitrypsin, was not observed when the amount of urokinase added or infused was relatively small, and conversion of plasminogen to plasmin was not extensive. The formation of plasmin-alpha2-macroglobulin complex was observed only when plasma plasminogen was activated with a larger amount of urokinase, and after most of the alpha2-plasmin inhibitor was consumed by forming complexes with plasmin. The formation of plasmin-alpha1-antitrypsin complex was not observed even in the highly activated plasma unless exogenous plasmin was added to the plasma. alpha2-Plasmin inhibitor was the only inhibitor of which the concentration in plasma was significantly decreased in patients with disseminated intravascular coagulation and fibrinolysis among the major plasmin inhibitors in plasma. The most reactive inhibitor for regulating plasma fibrinolysis very likely is alpha2-plasmin inhibitor.

Alpha-Globulins↗
PubMed1976

Isolation and characterization of alpha2-plasmin inhibitor from human plasma. A novel proteinase inhibitor which inhibits activator-induced clot lysis.

A procedure is presented for purifying a novel proteinase inhibitor in human plasma whose apparent unique biological property is to inhibit efficiently the lysis of fibrin clots induced by plasminogen activator. The final product is homogeneous as judged by disc gel electrophoresis, and immunoelectrophoresis. Its molecular weight estimated by sodium dodecyl sulfate gel electrophoresis or sedimentation equilibrium is 67,000 and 63,000, respectively. The inhibitor is a glycoprotein consisting polypeptide chain containing 11.7% carbohyrate. It migrates in the alpha2-globulin region in immunoelectrophoresis. The inhibitor is chemically and immunologically different from all the other known inhibitors in plasma. Inhibition of plasmin by the inhibitor is almost instantaneous even at 0 degrees, in contrast to the slow inhibition of urokinase (plasminogen activator in urine). Plasminogen activation by urokinase-induced clot lysis is inhibited by the inhibitor mainly through a mechanism of instantaneous inhibition of plasmin formed and not through the inhibition of urokinase. The inhibitor also inhibits trypsin. Consequently, it is suggested that this newly identified inhibitor is named alpha2-plasmin inhibitor or alpha2-proteinase inhibitor. A specific antibody directed against the inhibitor neutralizes virtually all inhibitory activity of plasma to activator-induced clot lysis. Immunochemical quantitation of the inhibitor was specific antiserum to the inhibitor and the purified inhibitor as a standard indicates that the concentration of the inhibitory in the serum of a healthy man is in or near the range of 5 to 7 mg/100 ml, which is the lowest concentration among the concentration of the proteinase inhibitors in plasma. The inhibitor and plasmin, trypsin, or urokinase form a complex which cannot be dissociated with denaturing and reducing agents. The formation of the enzyme-inhibitor complex occurs on a 1:1 molar basis and is associated with the cleavage of a unique peptide bone, which is most clearly demonstrated in the interaction of the inhibitor and beta-trypsin. In the complex formation between the inhibitor and plasmin, the inhibitor is cross-linked with the light chain which contains the active site of plasmin. It is suggested that, in a fashion analogous to complex formation between alpha1-antitrypsin and trypsin, the cross-links are formed between the active site serine of the enzyme and the newly formed COOH-terminal residue of the inhibitor, with cleavage of a peptide bond.

Amino Acids↗
PubMed1975

Plasmic degradation of bovine fibrinogen and non-crosslinked fibrins in solution and in gel form.

1. Analysis of degradation processes of bovine fibrinogen by bovine plasmin using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a study on the mode of changes of the properties related to clotting of digestion products as a function of time were performed. Gross features and patterns very similar to those which had been reported with human fibrinogen-plasmin systems were obtained. 2. Based on the molecular size of the degradation products and the mode of appearance and disappearance of the degradation products, the processes could tentatively be divided into three stages: stage 1, where fibrinogen (mol. wt 370 000) was degraded to produce fragments X1 (330 000) and X2 (290 000); stage 2, fragment X2 was degraded with appearance of Y (210 000) and D1 (140 000); stage 3, appearance of fragments D1, D2 (110 000), and D3 (100 000) sequentially and E (68 000) with concomitant disappearance of Y. 3. A microseparation method, which is a combination of dansylation and sodium dodecylsulfate-polyacrylamide gel electrophoresis, was devised to analyze the events of stage 1 in detail, and a molecular model for the process was proposed. 4. The plasmic degradation processes of bovine non-cross-linked fibrins in solution and in gel form were compared with that of fibrinogen and it was found that the state of the substrates, fibrins, could cause differences in the degradation patterns. With the former substrate, essentially the same sodium dodecyl sulfate-polyacrylamide gel electrophoretic patterns as those with fibrinogen were obtained. With the latter substrate, however, a distinct difference in the mode of degradation of beta chains was observed.

Animals↗
PubMed1975

Analysis of the fibrin-polymerizing reaction using sodium dodecylsulfate-agarose gel electrophoresis.

1. A new method of sodium dodecylsulfate gel electrophoresis, sodium dodecyl-sulfate-agarose gel electrophoresis, was developed. The new electrophoresis was shown to have a high and efficient resolving power for fibrin polymers and was also applicable to other proteins. 2. By sodium dodecylsulfate-agarose gel electrophoresis, the fibrin polymerizing reaction with activated fibrin stabilizing factor was analyzed in detail. The cross-linking between the gamma-chains was indicated to occur at an intermolecular level. The solubility of polymerized fibrin was suggested to be related mainly to the formation of the crosslinks between gamma-chains.

Animals↗
PubMed1975

Association of human alpha1-antitrypsin with anhydrotrypsin.

Unlike in the reaction of anhydrotrypsin and soybean trypsin inhibitor, human alpha1-antitrypsin was found not to form a complex with bovine anhydrotrypsin. This was shown using three different methods: electrophoresis, affinity chromatography on an anhydrotrypsin-coupled Sepharose column and equilibrium competitive binding assay. These results indicate the importance of the active site serine of trypsin in formation of a complex with alpha1-antitrypsin.

Animals↗
PubMedDate not supplied

Effect of captopril on acetylcholine-induced relaxation in the presence of nitroglycerin tolerance in isolated rabbit aorta.

We investigated the effects of angiotensin converting enzyme inhibitors on acetylcholine-induced endothelium-dependent vasodilation in the presence of nitroglycerin tolerance in rings of rabbit thoracic aorta mounted in tissue baths and precontracted with 10(-6) M norepinephrine. The vasorelaxant effects of acetylcholine were measured before and after 1 h treatment with 5 x 10(-4) M nitroglycerin. The acetylcholine dose-response curve shifted to the right after the induction of nitroglycerin tolerance. Pretreatment with captopril (a sulfhydryl angiotensin converting enzyme inhibitor), but not with M-1 (a metabolite of delapril and a nonsulfhydryl angiotensin converting enzyme inhibitor) restored acetylcholine-induced relaxation. Pretreatment with N-acetylcysteine also restored reduced acetylcholine-induced relaxation. These results suggest that the sulfhydryl group plays a major role in restoration of reduced acetylcholine-induced vasodilation in the presence of nitroglycerin tolerance.

Acetylcholine↗