Rogozhin V V, Verkhoturov V V
Yakutsk State Agricultural Academy, Yakutsk, 677002, Russia.
Biochemistry (Mosc). 1998 Jun;63(6):657-61.
Antioxidants (digoxin, quercetin, and ascorbic acid) inhibited the oxidation of o-dianisidine catalyzed by horseradish peroxidase. Digoxin bound with the enzyme-substrate complex which included a stable semioxidized product of o-dianisidine and inhibited horseradish peroxidase by the anticompetitive pattern, while the enzyme inhibition by quercetin followed the mixed pattern. The oxidation of ascorbic acid and o-dianisidine with their combined presence in the reaction mixture was differentiated. o-Dianisidine was oxidized after the oxidation of 90-100% of ascorbic acid was completed. The rate of peroxidase oxidation of ascorbic acid in the presence of o-dianisidine was more than two orders higher than the rate of its individual oxidation and 1.5-2.0 times higher than the rate of o-dianisidine oxidation. Feasible inhibition mechanisms of peroxidase oxidation of o-dianisidine are discussed.
抗氧化剂（地高辛、槲皮素和抗坏血酸）抑制了辣根过氧化物酶催化的邻联茴香胺氧化反应。地高辛与包含邻联茴香胺稳定半氧化产物的酶 - 底物复合物结合，并以反竞争性模式抑制辣根过氧化物酶，而槲皮素对酶的抑制遵循混合型模式。反应混合物中抗坏血酸和邻联茴香胺共同存在时，它们的氧化情况有所不同。在90 - 100%的抗坏血酸氧化完成后，邻联茴香胺才被氧化。在邻联茴香胺存在的情况下，抗坏血酸的过氧化物酶氧化速率比其单独氧化速率高两个数量级以上，比邻联茴香胺的氧化速率高1.5 - 2.0倍。文中讨论了邻联茴香胺过氧化物酶氧化的可能抑制机制。
