UREA DERIVATIVES AS TOOLS FOR STUDYING THE UREA-FACILITATED TRANSPORT-SYSTEM
UREA DERIVATIVES AS TOOLS FOR STUDYING THE UREA-FACILITATED TRANSPORT-SYSTEM
复制标题
DOI：
10.1007/bf00374960
复制
发表时间：
1993-04-01
影响因子：
4.5
通讯作者：
RIPOCHE, P
中科院分区：
文献类型：
--
作者：
MARTIAL, S;NEAU, P;RIPOCHE, P
在人红细胞膜（粉红色鬼）和抗利尿激素（ADH）刺激的青蛙膀胱上皮细胞中，尿素结构类似物对尿素易化扩散系统的影响进行了研究。在这两种组织中，尿素渗透性（P（尿素））显着但可逆地抑制了一些尿素类似物，如1-（3，4-二氯苯基）-2-硫脲（DCPTU）。该尿素衍生物以剂量依赖性方式降低尿素通量（在0.5mM浓度的DCPTU下，P（尿素）抑制90%）。为了获得红细胞和膀胱尿素转运系统的不可逆标记物，通过添加叠氮基残基（N3）对尿素衍生物进行了修饰，并进行了光亲和标记的初步实验。两种合成脲衍生物：1-（3-叠氮基-4-氯-苯基）-2-硫脲（ACPTU）和1-（3-叠氮基-4-氯-苯基）-3-甲基-2-硫脲（Me-ACPTU）在无光条件下使用时显示为P（尿素）的非常有效的抑制剂，在青蛙膀胱中测量的IC 50值分别为60.3 μ M和31.6 μ M。当在组织存在下照射时，这两种分子似乎都与青蛙膀胱和人粉红红细胞血影中的尿素载体共价结合：尿素通量在添加抑制剂后降至ADH存在下获得的值的30 - 70%，在制剂照射30分钟并去除抑制剂后仍保持较低水平。这些结果提供了一个有趣的方法，尿素载体的分析，特别是尿素或尿素类似物的结合位点上的运输蛋白。
The effects of urea structural analogues on the urea-facilitated diffusion system were examined in human red cell membranes (pink ghosts) and in antidiuretic hormone (ADH)-stimulated frog urinary bladder epithelia. In both tissues, urea permeability (P(urea)) was dramatically but reversibly inhibited by a number of urea analogues, such as 1-(3,4-dichlorophenyl)-2-thiourea (DCPTU). This urea derivative reduced the urea flux in a dose-dependent manner (90% inhibition of P(urea) at 0.5 mM concentration of DCPTU). With the aim of obtaining irreversible markers of red cell and urinary bladder urea transport systems, urea derivatives were modified by addition of an azido residue (N3) and preliminary experiments of photoaffinity labelling were carried out. Two synthetic urea derivatives: 1-(3-azido-4-chloro-phenyl)-2-thiourea (ACPTU) and 1-(3-azido-4-chloro-phenyl)-3-methyl-2-thiourea (Me-ACPTU) were shown to be very potent inhibitors of P(urea) when used in the absence of light, with IC50 values 60.3 muM and 31.6 muM respectively, as measured in frog urinary bladder. Both these molecules appeared to bind covalently to the urea carrier in both frog urinary bladder and human pink red cell ghosts, when illuminated in the presence of the tissue: the urea flux, which fell to 30 - 70 % of the value obtained in the presence of ADH after inhibitor addition, remained low after the preparation had been illuminated for 30 min and the inhibitor removed. These results provide an interesting approach to the urea carrier analysis, particularly to the urea or urea analogue binding site on the transport protein.