REGULATION OF GLUTAMIC-ACID DECARBOXYLASE DURING NEUROSPORA-CRASSA CONIDIAL GERMINATION
REGULATION OF GLUTAMIC-ACID DECARBOXYLASE DURING NEUROSPORA-CRASSA CONIDIAL GERMINATION
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DOI：
10.1128/jb.144.3.983-990.1980
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发表时间：
1980-01-01
影响因子：
3.2
通讯作者：
SCHMIT, JC
中科院分区：
文献类型：
--
作者：
CHRISTENSEN, RL;SCHMIT, JC
在经甲苯和甲醇渗透的萌发分生孢子和休眠分生孢子中测定了谷氨酸脱羧酶（GAD）的活性。粗草分生孢子的GAD活性是营养性菌丝的10倍。在分生孢子萌发过程中，GAD活性迅速下降到胚管出现前的低水平。萌发分生孢子GAD活性与谷氨酸代谢速率的下降密切相关。抑制蛋白质合成部分阻断了GAD活性的下降，但消除外源碳源并没有改变该酶的初始下降速度。当分生孢子在蒸馏水中孵育超过3小时时，GAD活性开始增加，最终达到与休眠分生孢子相当的水平。当分生孢子在蒸馏水中孵育时，GAD要么可逆失活，要么可以由内源性储存化合物合成。GAD可能是一种发育调节酶，负责催化分生孢子萌发过程中大量游离谷氨酸代谢的第一步。
Glutamic acid decarboxylase (GAD) from N. crassa was assayed in dormant and germinating conidia that had been permeabilized by toluene and methanol. N. crassa conidia contained 10 times the GAD activity found in vegetative mycelia. During conidial germination, GAD activity rapidly decreased to low levels before germ tubes appeared. GAD activity in germinating conidia closely followed the decreasing rate of glutamic acid metabolism. Inhibiting protein synthesis partially blocked the decrease in GAD activity, but eliminating exogenous carbon sources did not alter the initial rate of decrease in this enzyme. When conidia were incubated for more than 3 h in distilled water, GAD activity began to increase, and eventually reached levels comparable to those in dormant conidia. Either GAD was reversibly inactivated or this enzyme could be synthesized from endogenous storage compounds when conidia were incubated in distilled water. GAD may be a developmentally regulated enzyme that is responsible for catalyzing the first step in the metabolism of the large pool of free glutamic acid during conidial germination.