由于氧与血红蛋白平衡导致的氧同位素分馏。

Fractionation of oxygen isotopes due to equilibration of oxygen with hemoglobin.

作者信息

Pflug K P, Schuster K D

机构信息

Institute of Physiology I, University of Bonn, FRG.

出版信息

Adv Exp Med Biol. 1989;248:407-11. doi: 10.1007/978-1-4684-5643-1_45.

DOI:10.1007/978-1-4684-5643-1_45

PMID:2782162

Abstract

The aim of the study was to answer the question as to whether the chemical reaction of oxygen with hemoglobin exhibits a source of isotopic fractionation, which could be of significance in forming the overall fractionation effect of respiration recently determined in man. Investigations were performed on bovine hemoglobin solutions adjusted to normal values of Hb concentration and pH. After degassing in vacuo, the hemoglobin solution was equilibrated in a closed system with pure oxygen of suitable pressure so that oxygen saturation levels of 30, 50 and 100% were achieved. After complete equilibration, isotope analysis of oxygen by mass spectrometry resulted in 16O18O/16O2 ratios which were 0.35 +/- 0.02% lower in the oxygen bound to hemoglobin than that of the gas phase during all levels of oxygenation. Model calculations suggest the following: (1) the fractionation during oxygen uptake in the lung at rest is primarily determined by the reaction with hemoglobin, (2) the overall fractionation effect of respiration can be explained as due to single effects of the constituent processes when assuming the oxygen transport to be limited by utilization.

摘要

该研究的目的是回答氧气与血红蛋白的化学反应是否表现出同位素分馏源这一问题，这对于形成最近在人体中确定的呼吸总体分馏效应可能具有重要意义。对调整至血红蛋白浓度和pH正常水平的牛血红蛋白溶液进行了研究。在真空中脱气后，将血红蛋白溶液在封闭系统中与合适压力的纯氧平衡，以达到30%、50%和100%的氧饱和度水平。完全平衡后，通过质谱对氧气进行同位素分析，结果表明，在所有氧合水平下，与血红蛋白结合的氧气中的16O18O/16O2比值比气相中的低0.35±0.02%。模型计算表明：（1）静息时肺部吸氧过程中的分馏主要由与血红蛋白的反应决定；（2）当假设氧气运输受利用限制时，呼吸的总体分馏效应可解释为组成过程的单一效应所致。