加拉帕戈斯裂谷管虫厚巨穴虫（Pogonophora；Vestimentifera）的血红蛋白动力学

Hemoglobin Kinetics of the Galapagos Rift Vent Tube Worm Riftia pachyptila Jones (Pogonophora; Vestimentifera).

作者信息

Wittenberg J B, Morris R J, Gibson Q H, Jones M L

出版信息

Science. 1981 Jul 17;213(4505):344-6. doi: 10.1126/science.213.4505.344.

DOI:10.1126/science.213.4505.344

PMID:17819909

Abstract

Kinetics of the reactions of Riftia pachyptila hemoglobin with oxygen were followed spectrophotometrically by stopped-flow and laser flash photolysis techniques. The rate of oxygen dissociation increases eightfold over the range of 5 degrees to 20 degrees C (k = 2.2 sec(-1)at 10 degrees C). Oxygen recombination after flash photolysis was biphasic. The rates of both slow and fast phases of the reaction were independent of temperature from 0 degrees to 20 degrees C(k'fast = 7 x 10(6); k'slow = 1 x 16(6) liter mole (-1) sec(-1)). As the oxygen affinity is relatively temperature independent, analysis in terms of the two-state model of cooperativity requires that the conformational equilibrium constant L decrease by about 50-fold between 3 degrees and 15 degrees C.

摘要

利用停流分光光度法和激光闪光光解技术，对巨型管虫血红蛋白与氧气反应的动力学进行了跟踪研究。在5摄氏度至20摄氏度范围内，氧气解离速率增加了八倍（10摄氏度时k = 2.2秒⁻¹）。闪光光解后的氧气重组是双相的。反应的慢相和快相速率在0摄氏度至20摄氏度范围内均与温度无关（k'快 = 7×10⁶；k'慢 = 1×10⁶升·摩尔⁻¹·秒⁻¹）。由于氧气亲和力相对与温度无关，根据协同作用的二态模型进行分析表明，构象平衡常数L在3摄氏度至15摄氏度之间下降了约50倍。