Glycosidase and sulfatase activities and their possible role in keratan sulfate degradation in metamorphosing bonefish (Albula sp.) leptocephali.

During metamorphosis of leptocephalous larvae of the bonefish (Albula sp.), keratan sulfate, the principal glycosaminoglycan of the extracellular gelatinous body matrix, is degraded. Artificial substrates have been utilized to demonstrate the presence of β-N-acetylglucosaminidase, β-galactosidase and sulfatase activities in whole-body homogenates of early metamorphosing leptocephali. The concerted action of these enzymes has been shown to degrade the keratan sulfate polymer in other tissues. This paper describes the extraction, partial purification and some of the physical and kinetic properties of these enzymes. Additionally, starch gel electrophoresis was used to follow glycosidase activities in early, intermediate and advanced metamorphosing larvae. No differences were observed in electrophoretic migration or banding pattern of either β-N-acetylglucosaminidase or β-galactosidase during metamorphosis.