alpha-chymotrypsin and propylene-oxide

A new method of formation of non-covalent adducts based on an amphiphilic diblock copolymer of ethylene and propylene oxides with molecular mass of 2 kDa and alpha-chymotrypsin (ChT) under high pressure, has been developed. The composition of the complexes corresponds to seven polymer molecules per one ChT molecule in the pressure range of 1.1 to 400 MPa. The complexes fully retain the catalytic activity. Kinetic constants (Km and kcat) for enzymatic hydrolysis of N-benzoyl-L-tyrosine ethyl ester catalyzed by the complexes are identical with the corresponding values for native ChT. Analysis of kinetics of thermal inactivation of the complexes revealed that the constant of the rate of the slow inactivation step is markedly lower than for ChT.

Topics: Chymotrypsin; Epoxy Compounds; Ethylene Oxide; Hydrolysis; Kinetics; Molecular Weight; Polymers; Pressure

The ability of alpha-chymotrypsin to form complexes with amphiphilic block copolymer of ethylene oxide and propylene oxide upon heating up to 44-60 degrees C has been demonstrated for the first time. Depending on temperature and the initial component ratio, some complexes were obtained which varied in both composition and enzymatic activity. With a rise in the complexation temperature, the polymer content in the complex increased, while the enzymatic activity of the complex decreases. The complexes are very stable in water, but dissociate in 8 M urea and are characterized by enhanced thermal stability as compared with the original enzyme. It is assumed that both hydrophobic interactions and hydrogen bonds between the components are involved in the complex formation.

Topics: Chymotrypsin; Enzyme Stability; Epoxy Compounds; Ethylene Oxide; Hot Temperature; Polymers; Protein Denaturation

A classical soybean inhibitor of the Bowman-Birk type (BBI) with a copolymer of ethylene oxide and propylene oxide (PE) has been synthesized. The BBI-PE conjugate contain five covalently bound polymeric chains per one protein molecule and retains its capacity to inhibit trypsin (Ki = 10(-10) M), alpha-chymotrypsin (Ki = 7 x 10(-8) M) and human granulocyte elastase (Ki = 3 x 10(-8) M). The preservation of the antiproteinase activity in the antichymotrypsin center creates a prerequisite for the manifestation of the anticarcinogenic effect of the inhibitor.

Topics: Chymotrypsin; Epoxy Compounds; Ethylene Oxide; Leukocyte Elastase; Pancreatic Elastase; Polymers; Trypsin Inhibitor, Bowman-Birk Soybean

The reaction of the complex formation between beta-cyclodextrin and alpha-chymotrypsin conjugates with two-component ethylene oxide copolymers with propylene oxide has been described for the first time. The complex formation has been shown to depend on the mode of distribution of the polymer chains in the conjugate. The complex is a crystalline water-insoluble compound; its stoichiometric composition has been determined. The alpha-chymotrypsin conjugate with polyethylene glycol forms a water-soluble complex with beta-cyclodextrin.

Topics: Chymotrypsin; Cyclodextrins; Epoxy Compounds; Ethylene Oxide; Polymers