Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.54 (calpain 3)
 430 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calpain (Ca2+-dependent cysteine proteinase) was purified to apparent homogeneity from carp muscle by the method of DEAE-cellulose, hydroxylapatite and Ultrogel AcA 34 column chromatographies. The purified enzyme is classified as calpain II (high-Ca2+-requiring form of calpain) from the effects of Ca2+ concentration, pH and the antibiotics on the activity. Carp muscle calpain II was inhibited by rat liver calpastatin, the specific inhibitor for calpain. It is probable that the calpain-calpastatin system may play a biologically fundamental and common role in various cells, since the inhibitory effect of calpastatin on calpain from different tissues of different species is well conserved.
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PMID:Purification and properties of carp (Cyprinus carpio) muscle calpain II (high-Ca2+-requiring form of calpain). 299 71

Eye tissues contain splice variants of muscle-preferred p94 (calpain 3), such as lens-specific Lp82 and Lp85, retina-specific Rt88, and cornea-specific Cn94. The purpose of the present experiment was to analyze the activation and regulation of the best characterized p94 splice variant, Lp82. Recombinant rat Lp82 (rLp82) was expressed using the baculovirus system, purified with Ni-NTA affinity and DEAE-ion exchange chromatographies, and characterized by SDS-PAGE, casein zymography, and immunoblotting. After incubation with calcium, rLp82 autolyzed into two major fragments at approximately 60 and 22 kDa. Sequencing of the autolytic fragments showed loss of three amino acids from the N terminus and cleavage near the IS2 region. Also, Lp82 and calpain 2 were found to hydrolyze each other. Calpastatin inhibited calpain 2 activity, but not Lp82. Homology modeling suggested that the lack of inhibition of Lp82 by calpastatin was due to molecular clashes at the unique AX1 region of Lp82. Lp82 also hydrolyzed calpastatin. These results suggested that Lp82 might regulate other calpain activities and cause hydrolysis of substrates such as crystallins during lens cataract formation.
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PMID:Characterization and regulation of lens-specific calpain Lp82. 1190