ABSTRACT
Myorod (MR), a new thick filament protein of molluscan smooth muscles, is an alternatively spliced product of the myosin (Mn) heavy chain gene. We studied digestion of MR and Mn from the posterior adductor of Crenomytilus grayanus and the outer portion of adductor of Mizuchopecten (Patinopecten) yessoensis by papain and constructed the proteolytic substructure of MR, that is an analogue to Mn substructure. There are a head domain (analogue of Mn S1) and a rod domain (analogue of Mn rod); the junction between them is split at low ionic strength. The rod, in turn, consists of a neck domain (analogue of Mn S2) and a tail domain (identical to light meromyosin); the junction between them is split at high ionic strength. The localization and possible function of MR are discussed.
Subject(s)
Mollusca/chemistry , Muscle, Smooth/chemistry , Myosin Heavy Chains/chemistry , Alternative Splicing , Animals , Bivalvia/chemistry , Electrophoresis, Polyacrylamide Gel , Molecular Weight , Myosin Heavy Chains/metabolism , Myosins/chemistry , Myosins/metabolism , Osmolar Concentration , Papain/metabolism , Peptide Fragments/chemistry , Peptide Mapping , Protein Structure, TertiaryABSTRACT
The effect of modification of basic pancreatic trypsin inhibitor (BPTI) by derivatives of fatty acids (oleic, stearic) on the inhibition of bovine trypsin and human leukocyte elastase (HLE) was studied. Kinetic constants of interaction with trypsin and inhibition constants of both enzymes were determined. Hydrophobization of BPTI had virtually no effect on its high affinity for trypsin. The coupling of cis-unsaturated oleoyl radicals to the inhibitor molecule significantly increased the efficiency of HLE inhibition, whereas the coupling of saturated stearoyl radicals completely canceled the anti-elastase activity and in some cases promoted the substrate hydrolysis.
