Identification and characterization of a tissue kallikrein in rat skeletal muscles.
A tissue kallikrein was purified from rat skeletal muscle. Characterization of the enzyme showed that it has alpha-N-tosyl-L-arginine methylesterase activity and releases kinin from purified bovine low-Mr kininogen substrate. The pH optimum (9.0) of its esterase activity and the profile of inhibition by serine-proteinase inhibitors are identical with those of purified RUK (rat urinary kallikrein). Skeletal-muscle kallikrein also behaved identically with urinary kallikrein in a radioimmunoassay using a polyclonal anti-RUK antiserum. On Western-blot analysis, rat muscle kallikrein was recognized by affinity-purified monoclonal anti-kallikrein antibody at a position similar to that of RUK (Mr 38,000). Immunoreactive-kallikrein levels were measured in skeletal muscles which have different fibre types. The soleus, a slow-contracting muscle with high mitochondrial oxidative-enzyme activity, had higher kallikrein content than did the extensor digitorum longus or gastrocnemius, both fast-contracting muscles with low oxidative-enzyme activity. Streptozotocin-induced diabetes reduced muscle weights, but did not alter the level of kallikrein (pg/mg of protein) in skeletal muscle, suggesting that insulin is not a regulator of kallikrein in this tissue. Although the role of kallikrein in skeletal muscle is unknown, its localization and activity in relation to muscle functions and disease can now be studied.
Shimojo
N
N
Department of Medicine, Medical University of South Carolina, Charleston 29425.
Chao
J
J
Chao
L
L
Margolius
H S
HS
Mayfield
R K
RK
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D007610:Kallikreins / Q000276:immunology / Q000378:metabolism*; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology; D010447:Peptide Hydrolases / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D020840:Tissue Kallikreins; D014361:Trypsin Inhibitors / Q000494:pharmacology
D001786:Blood Glucose; D009124:Muscle Proteins; D014361:Trypsin Inhibitors; D010447:Peptide Hydrolases; C023073:tosylarginine methyl ester hydrolase; D007610:Kallikreins; D020840:Tissue Kallikreins