Kazushi Iwata
Roche Institute of Molecular Biology
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Collagen and related research | 1987
Shuji Kodama; Jun-Ichi Kishi; Kenichi Obata; Kazushi Iwata; Taro Hayakawa
Hybridoma antibodies against bovine collagenase inhibitor were produced by fusion of myeloma cells NS-1 (P3-NS1-1) with spleen cells from mice hyperimmunized with collagenase inhibitor purified from the explant medium of bovine dental pulps. Hybridomas positive by an enzyme-linked immunosorbent assay (ELISA) for bovine collagenase inhibitor were cloned by the dilution method. Seventeen hybridomas producing antibodies were isolated, four of which also recognized purified human collagenase inhibitor in the ELISA. Using a monoclonal antibody-Sepharose affinity column, we easily purified both bovine and human collagenase inhibitors to homogeneity. They showed the same mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, corresponding to a molecular mass of 32,000 daltons.
Matrix | 1989
Shuji Kodama; Kyoko Yamashita; Jun-Ichi Kishi; Kazushi Iwata; Taro Hayakawa
A sandwich enzyme immunoassay for collagenase inhibitor was set up with a pair of monoclonal antibodies prepared against bovine dental pulp collagenase inhibitor. Two different combinations of the antibodies were found to be applicable to the immunoassay; one was for the determination of both bovine and human collagenase inhibitors, but the other was only for the bovine one. Minimum sensitivity was 1 pg/tube (3 pg/ml) for bovine collagenase inhibitor and 1.5 pg/tube (5 pg/ml) for human inhibitor. The levels of collagenase inhibitor in several normal human body fluids were measured by the immunoassay, and the values obtained were as follows: serum, 183 +/- 30 ng/ml (mean +/- SD); platelet-poor plasma, 68 +/- 13; cerebrospinal fluid, 60 +/- 13; amniotic fluid, 1,780 +/- 969; tear fluid, 418 +/- 145; mixed saliva, 316 +/- 166; urine, 7 +/- 8.
Biochemical and Biophysical Research Communications | 1982
Kazushi Iwata; C.Y. Lai; Hamza A. El-Dorry; Richard L. Soffer
Abstract The NH 2 -and COOH-terminal sequences of the angiotensin-converting enzymes from rabbit lung and testis have been determined using less than 0.6mg of each protein. They are: (NH 2 )Thr-Leu-Asp-Pro-Gly-Leu-Leu-Pro-Gly-Asp- and -(Phe, Tyr)-Ser-Leu-Ala(COOH) for the pulmonary enzyme; and (NH 2 )Arg-Arg-Val-Ser-Asn-Asn-Gln-Ser-Ser- and -(Phe, Ala)-Glu-Leu-Ser(COOH) for the enzyme from testis.
Archives of Biochemistry and Biophysics | 1983
Kazushi Iwata; Russell Blacher; Richard L. Soffer; C.Y. Lai
The NH2-terminal sequence of 22 residues of rabbit lung angiotensin-converting enzyme has been determined as (NH2)Thr-Leu-Asp-Pro-Gly-Leu-Leu-Pro-Gly-Asp-Phe-Ala -Ala-Asp-Asn-Ala-Gly-Ala-Arg-Leu-Phe-Ala-. In the course of purification of the enzyme for structural analysis a protein of Mr = 82,000 with angiotensin-converting activity was separated from the major fraction containing the native enzyme (Mr = 140,000). This low-molecular-weight enzyme catalyzed the hydrolysis of the synthetic substrate Hip-His-Leu at a rate 23% of that with the native enzyme, and exhibited a similar Km value as well as behaviors towards various effectors of angiotensin-converting enzyme. Edman degradation of both the native and the 82K enzymes revealed that they contain identical amino acid sequences from the NH2-termini. This result and those of peptide mapping and carbohydrate and amino acid analyses indicate that the 82K enzyme is a fragment derived from the NH2-terminal portion of the native enzyme, and hence contains its catalytic site. Evidence has been obtained indicating that the active fragment was formed from the native enzyme during its elution from the antibody-affinity column with NH4OH: on treatment of the native enzyme (140K Mr) with 1 N NH4OH at room temperature, a cleavage occurred and two proteins with Mr = 82K and Mr = 62K were obtained. The 82K Mr fragment was found to be enzymatically active and to contain the same NH2-terminal sequence as the native enzyme. The other fragment (62K Mr) was devoid of the activity and was shown to derive from the COOH-terminal portion of the native enzyme by the peptide mapping and terminal analyses. Cleavage of a peptide bond with NH4OH is unusual and appears to be specific for the native angiotensin-converting enzyme from rabbit lung.
Gastroenterologia Japonica | 1991
Yoshihide Fukuda; Masami Imoto; Yasuo Koyama; Yuuji Miyazawa; Isao Nakano; Masami Hattori; Fumihiro Urano; Shuji Kodama; Kazushi Iwata; Taro Hayakawa
SummaryThe localization of tissue inhibitor of metalloproteinases (TIMP) in normal and pathological livers was examined by immunohistochemistry using monoclonal antibodies at the light microscopic level. In normal liver, immunoreactive TIMP was detected in smooth muscle cells and endothelial cells of blood vessels, fibroblasts, bile duct cells and Kupffer cells, indicating that TIMP is likely to be a general element of the liver. Immunoreactivity was observed in newly-formed blood vessels, proliferating bile ductules, and fibroblasts in the expanded portal area and fibrous septa of chronic active hepatitis and cirrhosis. TIMP was strongly stained in the capsule of hepatocellular carcinoma. The intensity of the immunoreaction in the capsule was generally greater than that in cirrhotic liver apart from the tumor mass. In three of five cases with hepatocellular carcinoma, endothelial walls in contact with tumor cells were positive.
Clinica Chimica Acta | 1992
Yukihiro Yokoya; Kazushi Iwata; Yasuteru Muragaki; Chiyo Shiota; Yoshifumi Morimoto; Masaya Inoue; Hidekazu Itoh; Shingo Nishioka; Akira Ooshima
Serum laminin (P1 fragment) and type IV collagen levels were determined in patients with hepatic disorders. The method was based on a sandwich enzyme-immunoassay using two monoclonal antibodies that recognize different epitopes of either laminin or type IV collagen molecule. Laminin and type IV collagen levels in the serum of patients with chronic hepatic disorders were higher as compared with those in healthy control subjects, with the increment of serum type IV collagen being far greater than that of laminin. Since type IV collagen and laminin are major basement membrane components, it is suggested that the higher levels of these peptides may reflect a so-called capillarization of the perisinusoidal wall encountered in hepatic fibrogenesis. The assay system used in this experiment is simple and sensitive and can be applied to clinical evaluation of hepatic fibrosis.
Biochemical and Biophysical Research Communications | 1988
Chiyoko N. Inoue; Kazuhiko Igarashi; Motoo Kitagawa; Kimio Terazono; Shin Takasawa; Kenichi Obata; Kazushi Iwata; Hiroshi Yamamoto; Hiroshi Okamoto
We have isolated a novel gene, rig (rat insulinoma gene) from rat insulinomas. In the present study, rig was found to be expressed in rat regenerating liver and in primary cultured rat hepatocytes. The level of rig mRNA was increased at the proliferative phase of liver regeneration. In synchronously cultured hepatocytes, the rig mRNA level was elevated at the G1 phase of the cell cycle and the rig-protein was accumulated in the nuclei during the S phase. These results indicated that rig could be involved in a more general way in growth or cell replication.
Journal of Immunological Methods | 1990
Shuji Kodama; Kazushi Iwata; Hisashi Iwata; Kyoko Yamashita; Taro Hayakawa
Clinica Chimica Acta | 1989
Kenichi Obata; Kazushi Iwata; Takafumi Ichida; Kyoichi Inoue; Eisaku Matsumoto; Yasuteru Muragaki; Akira Ooshima
Journal of Biochemistry | 1986
Yasuo Bai; Yasuteru Muragaki; Kenichi Obata; Kazushi Iwata; Akira Ooshima