Gross M T, Erman J E
Biochim Biophys Acta. 1985 Aug 8;830(2):140-6. doi: 10.1016/0167-4838(85)90021-4.
Upon heating cytochrome c peroxidase (ferrocytochrome c: hydrogen-peroxide oxidoreductase, EC 1.11.1.5) at pH 4 and 5, the enzyme precipitates at 41 degrees C and 51 degrees C, respectively. Incubating the enzyme at lower temperatures causes a slow dissociation of the heme from the protein. The heme precipitates, while the apoprotein remains soluble. Between pH 6 and 8, the native enzyme is converted to a low-spin ferric form upon heating. The Soret maximum shifts from 408 to 414 nm. The midpoint of this transition is pH-dependent, with a value of 46 degrees C at pH 6 decreasing to 29 degrees C at pH 8. At high temperatures the 414 nm form is converted to a species which has a 'free heme' spectrum with low absorptivity and Soret maximum at 390 nm. The midpoint temperature of this latter transition is 62 degrees C and 57 degrees C at pH 7 and 8, respectively.
在pH值为4和5的条件下加热细胞色素c过氧化物酶（亚铁细胞色素c：过氧化氢氧化还原酶，EC 1.11.1.5）时，该酶分别在41℃和51℃沉淀。在较低温度下孵育该酶会导致血红素从蛋白质中缓慢解离。血红素沉淀，而脱辅基蛋白仍可溶。在pH值6至8之间，天然酶在加热时会转化为低自旋铁形式。Soret峰从408 nm移至414 nm。此转变的中点取决于pH值，在pH值6时为46℃，在pH值8时降至29℃。在高温下，414 nm形式会转化为一种具有“游离血红素”光谱的物质，其吸收率低，Soret峰在390 nm。后一种转变的中点温度在pH值7和8时分别为62℃和57℃。
