Enzymatic properties and asparagine (Asn)-linked sugar-chain structures of N-acetyl beta-D-hexosaminidase A (Hex A) were compared in human tissues between normal renal cortex and renal cell carcinoma (RCC). No significant differences between the two Hex A preparations were observed with respect to enzymatic properties such as molecular mass, Michaelis-Menten value or optimal pH. With RCC preparations, relatively more Hex A passed through the concanavalin A (Con A) column, bound weakly to Con A, or bound strongly to Con A and also to the wheat germ agglutinin (WGA) column, than with preparations from normal renal cortex. In contrast, relatively less Hex A bound strongly to the Con A column, but passed through the WGA column with RCC preparations than with those from normal renal cortex. Asn-linked sugar-chain structures might apparently be altered during human renal oncogenesis.