Demonstration of beta-N-acetyl-D-glucosaminidase and beta-N-acetyl-D-hexosaminidase in Drosophila Kc-cells
1991
Sommer, U. | Spindler, K.D.
Kc-cells from Drosophila melanogaster, grown under serum-free conditions, produce two beta-hexosaminidases and secrete these enzymes into the medium. The two enzymes were separated by DEAE-exchange chromatography. According to their substrate specificities one enzyme is a beta-N-acetyl-D-glucosaminidase (E.C.3.2.1.30), the other one a beta-N-acetyl-d-hexosaminidase (E.C.3.2.1.52). The beta-N-acetyl-d-glucosaminidase is predominant in the medium, the beta-N-acetyl-D-hexosaminidase within the cells. The Km values for the substrates pNP-GlcNAc, pNP-GAlNAc, and (GlcNAc)2 are 0.8,16.73, and 1.67 mM for the beta-N-acetyl-d-glucosaminidase and 0.24, 0.44, and 0.2 mM for the beta-N-acetyl-D-hexosaminidase. Both enzymes are inhibited by the products and the beta-N-acetyl-d-glucosaminidase is also inhibited stereospecifically by the substrates pNP-GlcNAc and (GlcNAc)2- Both enzymes are inhibited in a partial competitive way by acetamidolactones, the Kis being as low as 0.1 KM.
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