The appearance of α-amylase activity during gut differentiation in sand dollar plutei☆

α-Amylase activity appears during gut differentiation of plutei of the sand dollar Dendraster excentricus. The activity increases coincidentally with that of a β-1, 3-glucanase. The α-amylase appears to have maltase activity. Glucose in the surrounding seawater depresses the increase in β-glucanase activity but does not affect the normal α-amylase increase. This suggests that the glucose repression of β-glucanase activity may be quite specific and not result from some general effect of glucose on metabolism. Sodium dodecyl sulfate-acrylamide gel electrophoresis resolves the larval α-amylase into components of 52,000 and 76,000 molecular weight. The α-amylase from the intestines of adult sand dollars resolves as a single component of 57,000 molecular weight. The pH curves for adult and larval α-amylases are also different and it is probable that adult and larval α-amylases are different proteins.