Studies on Proteinase in the Pyloric Caeca of Fishes-III

Substrate Specificity of Mackerel Proteinase

Abstract

The substrate specificity of mackerel proteinase has been investigated with the use of many synthetic substrates.
Mackerel proteinase hydrolysed the following substrates: Nα-benzoyl-L-arginine-amide, chloroacetyl-L-leucine, acetyl-DL-methionine and chloroacetyl-DL-methionine, while it did not hydrolyse the following substrates: carbobenzoxy-L-glutamyl-L-tyrosine, acetyl-L-tyrosineamide, Nα-benzoyl-L-tyrosineamide and ε-benzoyl-α-acetyl-DL-lysine. These results show that the proteinase has very broad specificity.
Effects of various metals on the activity of this enzyme were examined. No effect was brought forth by di-valent metal ions.
Experiments with N-acylated derivatives of amino acid, such as methionine and leucine, indicated that the proteinase has an optical specificity, i.e. it hydrolyses the L-isomer, but not the D-isomer. It may be of interest that this enzyme can be used for the optical resolution of acylated DL-amino acids.