Beta-hexosaminidase activities and isoenzymes in normal human ovary and ovarian adenocarcinoma

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Abstract
Levels and isoenzyme profiles of β-hexosaminidase were compared in extracts from normal ovaries and ovarian epithelial tumors. The specific activities of β-hexosaminidase were significantly (P < 0.001) higher in malignant than in normal ovarian tissues. The enzyme levels of the tumors depended on their degree of differentiation. Well-differentiated tumors had activities in the normal range, while poorly differentiated ones had values higher than the normal mean + 2 SD. The moderately and moderately to poorly differentiated tumors had intermediate levels. DEAE-cellulose chromatography was used to resolve the isoenzymes of β-hexosaminidase. Two major forms, β-hexoaminidase A and β-hexosaminidase B, were detected in all the preparations. In one tumor specimen, a component eluting slightly ahead of β-hexosaminidase A was also detected. For quick separation, a batch-wise procedure using DEAE-cellulose was adapted. Proportions of the isoenzymes A and B separated by batch-wise procedure were similar to those obtained by column chromatography. Heat stability, optimum pH, acid stability and substrate specificity of the β-hexomsaminidase isoenzymes from ovarian tissues were similar to those from other human sources. Isoenzymes from tumor extracts were more labile to heat and acid pH compared with those from normal source. Slight differences in the affinity for the substrate p-nitro-phenyl-β-N-acetyl-galactosaminide between the isoemzymes from normal and malignant ovaries were noted.