Substrate specificity of cathepsin H in untransformed tissues of mammary gland and in tissues of moderately differentiated form of lobular infiltrating breast cancer

Abstract

The substrate specifity of cathepsin H in untransformed tissues of mammary gland and in tissues of moderately differentiated form of lobular infiltrating breast cancer has been investigated. Cathepsin H from untransformed tissues of mammary gland hydrolyzed synthetic substrates in a row: Bz-Gly-Phe--->Z-Phe-Ala--->Z-Glu- Tyr--->oxytocin unlike enzyme from malignant tumor that did not hydrolyze the synthetic dipeptide Z-Glu-Tyr and revealed the substrate specificity in a row: Z-Phe-Ala--->Bz-Gly-Phe--->oxytocin. Cathepsin H has proteolytic endopeptidase activity to the substrate casein more pronounced for enzyme from untransformed tissue of mammary gland.

Keywords

• cathepsin H, tumor, mammary gland, substrate specifity