Cárdenas M E, Hansberg W
Centro de Inuestigacion sobre Fijacibn de Nitrbgeno, Uniuersidad Nacional Autbnoma de Mixico,Apartado Postal 565-A-Cuernauaca, Mor., Mexico.
J Gen Microbiol. 1984 Jul;130(7):1733-41. doi: 10.1099/00221287-130-7-1733.
During vegetative growth, glutamine is accumulated in the mycelium of Neurospora crassa. This high pool of glutamine seems to be required for aerial mycelium growth. Enzymes responsible for the synthesis and catabolism of glutamine were measured before and during the partial transformation of a mycelial mat into aerial mycelium. In the transforming mycelial mat,considerable activities of the biosynthetic NADP-glutamate dehydrogenase and glutamine synthetase (predominantly β polypeptide) and also some activity of glutamate synthase were observed. In the aerial mycelium, glutamine synthetase (predominantly β polypeptide) was detected, but very low activities of NADP-glutamate dehydrogenase and glutamate mycelium could derive from glutamine. No glutaminase activity could be detected. It is suggested that glutamate is formed through the activities of the glutamine transaminase-ω -amidase pathway and another transaminase. High activities of glutamine and alanine transaminases were observed in the aerial mycelium. These results are discussed in terms of the possible role of glutamine as a nitrogen carrier from the mycelium to the growing aerial hyphae.
在营养生长阶段，谷氨酰胺在粗糙脉孢菌的菌丝体中积累。这种高含量的谷氨酰胺似乎是气生菌丝体生长所必需的。在菌丝体垫部分转化为气生菌丝体之前和期间，对负责谷氨酰胺合成和分解代谢的酶进行了测定。在正在转化的菌丝体垫中，观察到生物合成型NADP -谷氨酸脱氢酶和谷氨酰胺合成酶（主要是β多肽）有相当高的活性，同时谷氨酸合酶也有一些活性。在气生菌丝体中，检测到了谷氨酰胺合成酶（主要是β多肽），但NADP -谷氨酸脱氢酶和谷氨酸合酶的活性非常低。气生菌丝体中的谷氨酸可能来源于谷氨酰胺。未检测到谷氨酰胺酶活性。有人提出，谷氨酸是通过谷氨酰胺转氨酶 - ω -酰胺酶途径和另一种转氨酶的活性形成的。在气生菌丝体中观察到谷氨酰胺转氨酶和丙氨酸转氨酶的高活性。从谷氨酰胺作为从菌丝体到生长中的气生菌丝的氮载体的可能作用方面对这些结果进行了讨论。
