Cystatins from bovine brain: Purification,some properties,and action on substance P degrading activity |
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Authors: | H G Aghajanyan A M Arzumanyan A A Arutunyan T N Akopyan |
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Institution: | (1) Institute of Experimental Biology, Hasratyan str. 7, 375044 Yerevan, Armenian SSR, USSR |
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Abstract: | 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°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 2.8×10–10 M for HMM-cystatin and 1.3×10–9 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.Abbreviations HMM-cystatin
high molecular mass inhibitor
- LMM-cystatin
low molecular mass inhibitor
- SP
substance P
- SPM
synaptosomal plasma membranes
- p-CMB
4-chloromercuribenzoic acid
- BK
bradykinin
- Bz-Arg-Nap
N-benzoyl-dl-arginine- -naphthylamide
- Arg-Nap
dl-arginine- -naphthylamide
- P-Pxy-Hb
hemoglobin initially coupled with pyridoxal-5 -phosphate |
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Keywords: | Cystatins purification substance P |
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