Department of Botany, University of California, Davis, California 95616.
Plant Physiol. 1967 Jun;42(6):791-6. doi: 10.1104/pp.42.6.791.
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.The presence of a cytokinin, such as benzyladenine, kinetin, BTP [6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine], or phenyladenine, in the culture solution could reproduce the effect of the embryonic axis. Other growth regulators did not produce this stimulation. High concentrations (1 mm) of all growth regulators examined were inhibitory. Various combinations of growth regulators failed to produce any synergistic effects. 6-Methylpurine inhibited the development of proteinase activity, and this inhibition was only partially restored by benzyladenine.A proteinase was partially purified from the cotyledons of 2-day-old squash seedlings and its synthesis was shown to be under the control of the embryonic axis.
从南瓜幼苗子叶中分离出一种粗制的蛋白水解酶制剂，该制剂能水解酪蛋白。乙二胺四乙酸或半胱氨酸的存在不会显著影响制剂的活性。在萌发过程中，完整胚胎的子叶中蛋白水解活性水平在第三天之前增加，然后降低。在萌发的头 32 小时内存在胚胎轴是最大限度地发展蛋白水解活性的前提条件。在培养液中添加细胞分裂素，如苄基腺嘌呤、激动素、BTP[6-(苄基氨基)-9-(2-四氢吡喃基)-9H-嘌呤]或苯腺嘌呤，可以再现胚胎轴的作用。其他生长调节剂则没有产生这种刺激作用。所检查的所有生长调节剂的高浓度（1mm）均具有抑制作用。各种生长调节剂的组合未能产生任何协同作用。6-甲基嘌呤抑制蛋白酶活性的发展，而这种抑制作用仅部分被苄基腺嘌呤所恢复。从 2 天大的南瓜幼苗子叶中部分纯化了一种蛋白酶，并证明其合成受胚胎轴的控制。
