Kornblatt J A, English A M, Hui Bon Hoa G
Eur J Biochem. 1986 Aug 15;159(1):39-43. doi: 10.1111/j.1432-1033.1986.tb09830.x.
The effects of pressure on cytochrome c peroxidase [CcP(FeIII)], its cyano derivative (CcP X CN) and its enzyme-substrate complex (ES) have been studied. The effects of pressure on the binding of the substrate analog porphyrin cytochrome c (porphyrin c) to CcP X CN and ES have also been studied. High pressure causes CcP(FeIII) to undergo a high-spin to low-spin transition but has no detectable effect on either CcP X CN, which is already low spin, or on ES. The low-spin CcP(FeIII) structure at pressure is similar to the low-spin form at low temperature and the low-spin form of horseradish peroxidase at high pressure. delta V degree associated with the spin equilibrium is about 30 ml/mol and is independent of temperature. delta G degree is small, 4.7 kJ/mol at 0 degree C, while delta H degree is 14.2 kJ/mol at 1 bar (100 kPa). Pressure has no detectable effect on the binding equilibria of mixtures of CcP X CN plus porphyrin c or ES plus porphyrin c. This indicates that the interaction of CcP and porphyrin c results in little or no volume change; the same is true in the case of cytochrome c oxidase and porphyrin c.
研究了压力对细胞色素c过氧化物酶[CcP(FeIII)]、其氰基衍生物（CcP X CN）及其酶-底物复合物（ES）的影响。还研究了压力对底物类似物卟啉细胞色素c（卟啉c）与CcP X CN和ES结合的影响。高压导致CcP(FeIII)发生高自旋到低自旋的转变，但对已经是低自旋的CcP X CN或ES没有可检测到的影响。压力下的低自旋CcP(FeIII)结构类似于低温下的低自旋形式和高压下辣根过氧化物酶的低自旋形式。与自旋平衡相关的ΔV°约为30 ml/mol，且与温度无关。ΔG°很小，在0℃时为4.7 kJ/mol，而在1巴（100 kPa）时ΔH°为14.2 kJ/mol。压力对CcP X CN加卟啉c或ES加卟啉c混合物的结合平衡没有可检测到的影响。这表明CcP与卟啉c的相互作用导致的体积变化很小或没有；细胞色素c氧化酶与卟啉c的情况也是如此。
