Plasma protein binding and endothelial enzyme interactions in the lung.
Plasma protein binding and endothelial enzyme interactions in the lung.
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肺中血浆蛋白结合和内皮酶相互作用。
DOI：
10.1152/jappl.1989.66.6.2617
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Roerig,DL
中科院分区：
文献类型：
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作者：
Linehan,JH;Dawson,CA;Bongard,RD;Bronikowski,TA;Roerig,DL
在离体兔肺灌流含5%牛血清白蛋白（BSA）或5%右旋糖酐（Dextran）的盐溶液中，研究了合成的血管紧张素转换酶（ACE）底物[~ 3 H]苯甲酰苯丙氨酰丙氨酰脯氨酸（BPAP）与血浆白蛋白结合对肺内皮ACE水解BPAP的影响。采用单程指示剂稀释法测定水解产物[3 H]BPAP的分数（M）。肺M是更大的白蛋白自由灌注液比BSA时存在。M随着BPAP在到达肺之前与BSA接触的时间（ti）增加而降低，表明BPAP的一些BSA结合位点在推注通过肺期间不平衡。使用结合BPAP和BSA的快速和缓慢结合动力学的模型将M对ti数据关联。对于缓慢的BPAP-BSA相互作用，解离速率常数约为0.015 s-1，在平衡时结合到这些缓慢平衡位点的BPAP的分数约为22%。结果表明，瞬时血浆蛋白结合动力学可以影响肺BPAP水解。
The influence of plasma albumin binding of the synthetic angiotensin-converting enzyme (ACE) substrate [3H]benzoyl-phenylalanyl-alanyl-proline (BPAP) on BPAP hydrolysis by pulmonary endothelial ACE was studied in isolated rabbit lungs perfused with a salt solution containing either 5% bovine serum albumin (BSA) or 5% dextran. The single-pass indicator-dilution method was used to measure the fraction (M) of [3H]BPAP hydrolyzed. Lung M was greater with albumin-free perfusate than when BSA was present. M decreased as the time (ti) that the BPAP was in contact with the BSA before reaching the lung was increased, suggesting that some BSA binding sites for BPAP were not in equilibrium during bolus transit through the lungs. The M vs. ti data were correlated using a model incorporating both rapid and slow binding kinetics of BPAP and BSA. For the slow BPAP-BSA interaction, the dissociation rate constant was approximately 0.015 s-1, and the fraction of the BPAP bound to these slowly equilibrating sites at equilibrium was approximately 22%. The results indicate that transient plasma protein binding kinetics can affect lung BPAP hydrolysis.