A cathepsin B-like enzyme from mackerel white muscle is a precursor of cathepsin B.
A cathepsin B-like enzyme from the white muscle of common mackerel Scomber japonicus was a cysteine protease that hydrolyzed Z-Arg-Arg-MCA, the substrate for cathepsin B. In a partial purified cathepsin B-like enzyme preparation at 4 degrees C left over time, a converted enzyme that hydrolyzes Z-Arg-Arg-MCA and Z-Phe-Arg-MCA appeared in the preparation. The converted enzyme was purified from the cathepsin B-like enzyme, characterized and was identified as mackerel cathepsin B. These results suggested that the mackerel cathepsin B-like enzyme was a precursor of cathepsin B. Mackerel cathepsin B formed in the purified cathepsin B-like enzyme preparation by adding of a small amount of the purified cathepsin B to the preparation. Therefore, mackerel cathepsin B-like enzyme was converted to the mature form of cathepsin B by autoactivation. The conversion of the cathepsin B-like enzyme (molecular mass 60 kDa) to cathepsin B (molecular mass 23 kDa) was detected by immunoblotting by using human anti-(cathepsin B) antibody. The intermediate forms of 40 kDa and 38 kDa were also detected during the conversion.
Aoki
Takahiko
T
Faculty of Bioresources, Mie University, Kamihama 1515, Tsu Mie 514-8507, Japan. aoki@bio.mie-u.ac.jp
Yokono
Masaki
M
Ueno
Ryuji
R
D000818:Animals; D015153:Blotting, Western; D002401:Cathepsin B / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology* / Q000378:metabolism; D010473:Perciformes / Q000378:metabolism*; D013379:Substrate Specificity
D004792:Enzyme Precursors; D002401:Cathepsin B