Verezin I C, Ugarova N N, Kershchengolbts B M, Brovko L I
Biokhimiia. 1975 Mar-Apr;40(2):297-301.
Constants of inactivation rate of horseradish peroxidase (HRP) apo-HRP and apo-HRP-protoporphyrin (PP) are estimated at the pH range 2.8-12.8 and 25 degrees C. Two ionogenic groups (acid and alkaline) are detected on cases of HRP and apo-HRP, which are responsible for stable HRP conformation. HRP stability within the pH range 5-10 exceeded 30 times that of apo-HRP, while the stability apo-HRP-PP complex is similar to that of apo-HRP. The data obtained show that formation of complex of apo-HRP with PP, an analogue of the prostetic group lacking central Fe atom, practically does not affect the stability of HRP protein globula at pH 5-10, but significantly stabylized apo-HRP at the extreme pH values. The complex formation of apo-HRP with active prosthetic group - hemin - results on the stable conformation of the HRP protein globula, which suggests a determining role of Fe ion - porphyrin complex (hemin) on the support of the stable HRP structure.
在25摄氏度、pH值范围为2.8至12.8的条件下，估算了辣根过氧化物酶（HRP）脱辅基HRP和脱辅基HRP-原卟啉（PP）的失活速率常数。在HRP和脱辅基HRP的情况下检测到两个离子化基团（酸性和碱性），它们负责稳定HRP的构象。在pH值范围5至10内，HRP的稳定性比脱辅基HRP高出30倍，而脱辅基HRP-PP复合物的稳定性与脱辅基HRP相似。所获得的数据表明，脱辅基HRP与PP（缺乏中心铁原子的辅基类似物）形成复合物，在pH值5至10时实际上不会影响HRP蛋白球状体的稳定性，但在极端pH值下会显著稳定脱辅基HRP。脱辅基HRP与活性辅基血红素形成复合物，导致HRP蛋白球状体的稳定构象，这表明铁离子-卟啉复合物（血红素）在维持HRP稳定结构方面起决定性作用。
