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

A novel myofibril-bound serine proteinase inhibitor (MBSPI) was purified to homogeneity from the skeletal muscle of lizard fish (Saurida wanieso). Pur ification was carried out by ammonium sulfate fractionation, followed by co lumn chromatographies on DEAE-Sephacel, SP-Sepharose and Sephadex G-150. MB SPI 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-PAGE 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, bovin e chymotrypsin. two trypsins from carp hepatopancreas and a serine proteina se isolated from the sarcoplasmic fraction of white croaker muscle. It does not exert any inhibitory activity toward a myofibril-bound serine proteina se: from carp muscle. (C) 2001 Elsevier Science Inc. All rights reserved.