Hormonal Control of Proteinase Activity in Squash Cotyledons

Abstract

A crude proteolytic enzyme preparation which hydrolyzes casein was isolated from the cotyledons of squash seedlings. The presence of ethylene diamine tetraacetate or cysteine did not appreciably affect the activity of the preparation. During the course of germination, the level of proteolytic activity increased in the cotyledons of intact embryos through the third day and then decreased. The presence of the embryonic axis during the first 32 hours of germination was a prerequisite for the development of maximum proteolytic activity.