MgATP可刺激胱氨酸从正常白细胞中流出。
Cystine exodus from normal leucocytes is stimulated by MgATP.
作者信息
Greene A A, Clark K F, Smith M L, Schneider J A
机构信息
Department of Pediatrics, University of California, San Diego, La Jolla 92093.
出版信息
Biochem J. 1987 Sep 1;246(2):547-9. doi: 10.1042/bj2460547.
Cystine exodus from partially purified granular fractions of normal leucocytes is stimulated by MgATP. N-Ethylmaleimide, an inhibitor of the lysosomal H+-translocating ATPase, eliminated the stimulated exodus, but had no effect on basal exodus. As the initial content of cystine was increased, the initial velocity of both the basal and ATP-stimulated egress increased. However, as saturation with substrate was approached, the ATP stimulation disappeared leaving only the N-ethylmaleimide-insensitive basal exodus. The increased initial velocity in the presence of ATP may represent improved binding of cystine to the partially saturated inner transporter as a result of conformational or charge optimization brought about by the action of the H+-translocating ATPase.
MgATP可刺激胱氨酸从正常白细胞部分纯化的颗粒组分中流出。溶酶体H⁺转运ATP酶的抑制剂N-乙基马来酰亚胺消除了这种刺激流出，但对基础流出没有影响。随着胱氨酸初始含量的增加，基础流出和ATP刺激流出的初始速度均增加。然而，当接近底物饱和时，ATP刺激消失，仅留下对N-乙基马来酰亚胺不敏感的基础流出。ATP存在时初始速度的增加可能代表由于H⁺转运ATP酶的作用导致构象或电荷优化，从而使胱氨酸与部分饱和的内部转运体的结合得到改善。
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