Purification and characterization of an inducible cysteine proteinase inhibitor from submandibular glands of isoproterenol-treated rats.
A low-molecular-weight protein, induced in rats following prolonged isoproterenol treatment, has been purified from rat submandibular glands by chromatography on columns of Sepharose CL-6B, DEAE-Sepharose CL-6B, and Sephadex G-75. The purified protein is homogeneous based on gel electrophoresis and Ouchterlony double diffusion. The molecular weight of the purified protein was 14,000 and 15,500 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration on a Superose 12 column, respectively. This protein contains 31% glutamic acid/glutamine and aspartic acid/asparagine, 3.6% cysteine, and 2.5% proline. This protein is shown to be an inhibitor of several cysteine proteinases, papain and ficin being inhibited very strongly in approximately 1:1 molar ratio of enzyme to inhibitor. The protein is not detected in normal rat tissues but is induced in submandibular and sublingual glands even after 1 day of isoproterenol treatment of rats as early as 7 days after birth. Based on cysteine proteinase inhibitor activity, molecular size, and chemical composition this protein appears to belong to the cystatin superfamily.
Bedi
G S
GS
Department of Oral Biology, School of Dental Medicine, State University of New York, Buffalo 14214.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D015853:Cysteine Proteinase Inhibitors; D007122:Immunoelectrophoresis; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D008970:Molecular Weight; D011480:Protease Inhibitors / Q000302:isolation & purification*; D051381:Rats; D011919:Rats, Inbred Strains; D012463:Saliva / Q000032:analysis; D012471:Salivary Proteins and Peptides / Q000302:isolation & purification*; D013363:Submandibular Gland / Q000032:analysis* / Q000187:drug effects
D000596:Amino Acids; D015853:Cysteine Proteinase Inhibitors; D011480:Protease Inhibitors; D012471:Salivary Proteins and Peptides; D007545:Isoproterenol