[Isolation and properties of fish chymopsin]

A simple and convenient method of fish chymopsin isolation from the acetone powder of pyloric appendices has ben developed using classical methods. The enzyme preparation includes 62-65% of protein, the specific weight of trypsin and chymopsin being 1000 and 3000 units per 1 mg of protein, respectively. Heterogeneity of the isolated chymopsin was shown using electrophoresis in PAAG. As to the degree of purity the given preparation is like to the bull chymopsin. Under identification of amino acid composition it is shown that the both chymopsins differ from each other to a certain extent. The preparation isolated from fish includes the less content of lysine that probably can evidence for the overwhelming quantity of serine proteases in anionic form as well as the less content of serine and leucine. At the same time the higher content of threonine, glutamic acid, proline, methionine is revealed in the fish chymopsin. Enzymatic properties of fish chymopsin as to the digestion of some low-molecular substrates have been studied. A comparative characteristic of their hydrolysis by the isolated preparation, bull chymopsin and pylochymopsin (fish preparation isolated on the biospecific sorbent) is presented. At any case the degree of hydrolysis of substrates by the both chymopsines is similar and to some extent different from the catalytic action of pylochymopsin.