Yoshifumi Watazu
Kumamoto University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Yoshifumi Watazu.
Bioscience, Biotechnology, and Biochemistry | 2000
Koji Kishi; Yoshifumi Watazu; Yoshiaki Katayama; Hiroaki Okabe
Mass production of an r-CDH derived from Nocardia species was made possible by gene technology. (Horinouchi et al., Applied and Environmental Microbiology, 57, 1386-1393 (1991)). However, the characteristics of the r-CDH have not been studied in detail and have not been improved enough for industrial use. We accordingly characterized both the native-CDH and the r-CDH prepared from Streptomyces lividans. Both CDHs were monomers with molecular masses of 37 kDa. The K m of r-CDH was 2.50×10-3 M for cholesterol and 2.33×10-4 M for NAD. The activators of CDHs were TritonX-100 and cholate. TritonX-405, Ag+, and Zn2+ inhibited both enzymes. The residual activity of native CDH after heat treatment was 32% (37°C, 60 min), while the r-CDH showed a residual activity of 87% (37°C, 60 min). The r-CDH is an enzyme with high substrate specificity for cholesterol as well as native CDH and higher thermal stability than native CDH. We have developed a novel serum cholesterol assay using the r-CDH, which permits the direct measurement of cholesterol by measuring NADH reaction products. We conclude that this r-CDH enzyme is useful and can be used to measure cholesterol in a clinical chemistry setting.
Clinical Biochemistry | 1990
Yoshifumi Watazu; Hiroaki Okabe; Hiroyuki Sugiuchi; Yoshinori Uji; Yasushi Shirahase; Nobuaki Kaneda
A new proteolytic measurement of serum mitochondrial aspartate aminotransferase was evaluated using cytosolic aspartate aminotransferase inactivating protease. Some of the proteases, such as, alpha-chymotrypsin, subtilisin and cytosolic aspartate aminotransferase inactivating protease 401 from Streptomyces species, also specifically inactivated cytosolic aspartate aminotransferase, but not mitochondrial, aspartate aminotransferase. The protease 401 was the most heat stable for storage and showed a higher inactivation rate for cytosolic aspartate aminotransferase--up to 7000 IU/L--more than 200-fold the upper limit. The coefficient of variation of the proteolytic method was less than 10%. Results by the present method correlated with those by the immunochemical method (r = 0.970) and the regression curve was Y = 0.95X + 1.60 (Y: immunochemical method; X: proteolytic method). In the present assay system, reference values for mitochondrial aspartate aminotransferase activity in 500 healthy people ranged from 2.0-7.2 U/L (mean 3.8 U/L).
Archive | 1998
Koji Kishi; Tsutomu Kakuyama; Yasushi Shirahase; Yoshifumi Watazu
Archive | 1992
Tsuyoshi Ohno; Masaru Suzuki; Tatsuo Horiuchi; Yasushi Shirahase; Koji Kishi; Yoshifumi Watazu
Journal of Clinical Laboratory Analysis | 1993
Yoshifumi Watazu; Yoshinori Uji; Hiroaki Okabe; Yasushi Shirahase; Nobuaki Kaneda; Arthur Karmen
Archive | 1990
Yasushi Shirahase; Yoshifumi Watazu
Bioscience, Biotechnology, and Biochemistry | 1994
Yoshifumi Watazu; Katashi Nagamatsu; Yasushi Shirahase; Nobuaki Kaneda; Sawao Murao; Hiroaki Okabe
Journal of Clinical Laboratory Analysis | 1990
Hiroaki Okabe; Yoshinori Uji; Hiroyuki Sugiuchi; Yoshifumi Watazu; Yasushi Shirahase; Nobuaki Kaneda
Archive | 1999
Toshiyuki Baba; Hiromasa Tabata; Katashi Nagamatsu; Yoshifumi Watazu; Ryoji Aoki
Archive | 1999
Toshiyuki Baba; Hiromasa Tabata; Katashi Nagamatsu; Yoshifumi Watazu; Ryoji Aoki