Gientka-Rychter A, Cherry J H
Horticulture Department, Purdue University, Lafayette, Indiana 47907.
Plant Physiol. 1968 Apr;43(4):653-9. doi: 10.1104/pp.43.4.653.
Germination of peanut seed is accompanied by a rapid increase in isocitritase (isocitrate lyase, EC 4.1.3.1) during the first 4 days. The presence of cycloheximide (50 mug/ml) during water imbibition inhibited the increase in isocitritase activity. Actinomycin D conversely did not inhibit isocitritase activity until the second day of imbibition while RNA synthesis was inhibited. Germination of peanut seed in (14)C-reconstituted amino acids followed by fractionation of a 20 to 35% ammonium sulfate preparation on a Sephadex G-200 column (57-fold purification) showed that the active enzymic fraction coincided with a large peak of radioactivity. Germination of peanut seed in 45% D(2)O followed by enzyme purification and CsCl equilibrium centrifugation revealed that all the enzyme from D(2)O seed had a higher density than normal isocitritase. These data indicate that isocitritase in peanut seed is synthesized de novo.
花生种子萌发的头4天里,异柠檬酸裂解酶(异柠檬酸裂合酶,EC 4.1.3.1)迅速增加。吸胀期间加入放线菌酮(50微克/毫升)会抑制异柠檬酸裂解酶活性的增加。相反,放线菌素D直到吸胀第二天RNA合成受到抑制时才抑制异柠檬酸裂解酶活性。用(14)C标记的氨基酸培育花生种子,然后在葡聚糖G-200柱上对20%至35%硫酸铵制剂进行分级分离(纯化57倍),结果表明活性酶组分与一个大的放射性峰相一致。用45% D(2)O培育花生种子,随后进行酶纯化和CsCl平衡离心,结果显示来自D(2)O种子的所有酶的密度都高于正常异柠檬酸裂解酶。这些数据表明花生种子中的异柠檬酸裂解酶是重新合成的。