Preclinical increase in activity of muscle microsomal trypsin-like protease in murine muscular dystrophy, C57BL/10-mdx

• Published in: FEBS letters 1986-04, Vol.199 (2), p.193-197
• Main Authors: Sawada, Hitoshi, Tsuji, Shigekatsu, Kusumoto, Shigeo, Doi, Yoshio, Matsushita, Hiroshi
• Format: Article
• Language: English
• Subjects: Aging; Animals; Biological and medical sciences; Endopeptidases - metabolism; Enzyme activity; Kinetics; mdx mouse; Medical sciences; Mice; Mice, Inbred C57BL; Microsomes - enzymology; Muscle Development; Muscles - enzymology; Muscular dystrophy; Muscular Dystrophy, Animal - enzymology; Nervous system involvement in other diseases. Miscellaneous; Neurology; Protease; Subcellular Fractions - enzymology; Substrate Specificity; Tissue Distribution; Trypsin; Trypsin-like enzyme
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(86)80478-1

Preclinical alterations of protease activities in skeletal muscles from 10-day-old dystrophic mouse, C57BL/10-mdx, were examined by using 10 fluorogenic peptide substrates. Among the activities tested, only Boc-Val-Pro-Arg-MCA-hydrolyzing enzyme of the muscle microsomes showed an about 6-fold higher level of activity in mdx mouse. The increase in activity was not observed in tissues other than skeletal muscle. The enzyme had a pH optimum between 8.5 and 11.0, and was inhibited with DFP and variety of trypsin inhibitors. The enzymatic activity transiently increased at 1-2 weeks of age, the preclinical or very early stage of the disease. These results imply that the increased level of a trypsin-like protease possibly present in muscle microsomes may be closely related to the manifestation of muscular dystrophy.