Cooperstein D F, Scott W N
Invest Ophthalmol Vis Sci. 1978 Apr;17(4):370-3.
We have examined the effects of ascorbate upon amino acid uptake by the in vitro toad cornea. Physiologic levels of ascorbate increase the uptake of leucine by approximately 35% but have no effect upon the uptake of alanine. Uncouplers of oxidative phosphorylation do not inhibit the stimulation by ascorbic acid of leucine accumulation, indicating the increased synthesis of ATP is not the mechanism; exogenous ATP, unlike ascorbate, stimulates the uptake of both alanine and leucine. Carbon monoxide blocks the effects of ascorbate, whereas 2-heptyl-4-hydroxyquinoline-N-oxide (HOQNO), which inhibits "reverse" electron transfer, enhances the accumulation of leucine. The evidence suggests that ascorbate serves as an energy source for the uptake of leucine.
我们研究了抗坏血酸盐对体外培养的蟾蜍角膜摄取氨基酸的影响。生理水平的抗坏血酸盐可使亮氨酸的摄取增加约35%，但对丙氨酸的摄取没有影响。氧化磷酸化解偶联剂并不抑制抗坏血酸对亮氨酸积累的刺激作用，这表明ATP合成增加不是其作用机制；与抗坏血酸盐不同，外源性ATP可刺激丙氨酸和亮氨酸的摄取。一氧化碳可阻断抗坏血酸盐的作用，而抑制“逆向”电子传递的2-庚基-4-羟基喹啉-N-氧化物（HOQNO）可增强亮氨酸的积累。证据表明，抗坏血酸盐作为亮氨酸摄取的能量来源。
