Purification of a novel myofibril-bound serine proteinase inhibitor (MBSPI) from the skeletal muscle of lizard fish

摘要

A novel myofibril-bound serine proteinase inhibitor (MBSPI) was purified to homogeneity from the skeletal muscle of lizard fish (Saurida wanieso ). Purification was carried out by ammonium sulfate fractionation, followed by column chromatographies on DEAE-Sephacel, SP-Sepharose and Sephadex 0-150. MBSPI was purified 7.7-fold starting from the DEAE-Sephacel fraction, with a yield of 0.2%. It is a monomeric protein with the molecular mass of 50 kDa as estimated by SDS-PAOE and gel filtration. MBSPI reveals high inhibition specificity toward a myofibril-bound serine proteinase (MBSP) purified from lizard fish muscle. No inhibition is detected toward bovine trypsin, bovine chy- motrypsin, two trypsins from carp hepatopancreas and a serine proteinase iso'ated from the sarcoplasmic fraction of white croaker muscle. It does not exert any inhibitory activity toward a myofibril-bound serine proteinase from carp muscle.