Cystatins from bovine brain: purification, some properties, and action on substance P degrading activity.
Two cystatins were purified from tissue extract of bovine brain by alkaline treatment, acetone fractionation, gel chromatography on Sephadex G-75, and affinity chromatography on S-carboxymethyl-papain-Sepharose. One of the inhibitors had a relatively high molecular mass, 25 kDa (HMM-cystatin) with pI 4.7, and the other, 11 kDa (LMM-cystatin) with pI 5.23. Both inhibitors showed considerable stability at pH 2 and 80 degrees C. The cystatins inhibited papain, ficin, and cathepsins B and H, but not trypsin, chymotrypsin, thermolysin, nagarse, and cathepsin D. Ki values for the complexes of papain and the inhibitors were estimated to be 2.8 x 10(-10) M for HMM-cystatin and 1.3 x 10(-9) M for LMM-cystatin. Both purified cystatins prevented degradation of substance P by soluble fraction and lysosomal extract obtained from synaptosomes, but did not suppress the cleavage of the peptide by synaptosomal plasma membranes.
Aghajanyan
H G
HG
Institute of Experimental Biology, Armenian SSR.
Arzumanyan
A M
AM
Arutunyan
A A
AA
Akopyan
T N
TN
D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D055316:Cystatin C; D015891:Cystatins; D004791:Enzyme Inhibitors / Q000378:metabolism*; D008970:Molecular Weight; D011506:Proteins / Q000302:isolation & purification* / Q000378:metabolism; D013373:Substance P / Q000378:metabolism*
D055316:Cystatin C; D015891:Cystatins; D004791:Enzyme Inhibitors; D011506:Proteins; D013373:Substance P