Occurrence of alpha-amylase in the axis of germinating peas.

alpha-Amylase was found in the axis portion of ungerminated pea seeds (Pisum sativum var. Alaska). The occurrence of this enzyme was demonstrated with crude homogenates (also containing beta-amylase) using three different methods: the hydrolysis of beta-limit dextrin, the change in absorption spectra for the iodine-starch complex, and the increase in reducing materials relative to the decrease in starch. The first method was used to quantitate the changes in alpha-amylase activity during germination. The increase in total amylase activity (primarily beta-amylase) paralleled germination; the accumulation of alpha-amylase activity was not initiated for an additional day. The increased alpha-amylase activity was related to epicotyl growth. Approximately half of this activity was found in the etiolated stem, the distribution being higher in growing than in nongrowing portions.