Takikawa S, Kitayama-Yokokawa C, Tsusue M
J Biochem. 1979 Mar;85(3):785-90.
A pterin deaminase catalyzing the hydrolytic deamination of various pteridines was found in the bacterium, Bacillus megaterium, and partially purified from bacterial extract. The specific activity was raised 90-fold over that of the crude extract. The pH optimum is around 7.3, and the Km value for 6-carboxypterin is 1.3 mM. The molecular weight of the enzyme was estimated by gel filtration to be about 110,000. The enzyme deaminated pterin, 6-carboxypterin, biopterin, 6-methylpterin, 7-methylpterin, xanthopterin, 6-hydroxymethylpterin, sepiapterin, isosepiapterin, folic acid, and 6,7-dimethylpterin to their corresponding lumazines, whereas guanine, 7-carboxypterin, leucopterin, isoxanthopterin, and 6-methylisoxanthopterin did not serve as substrates. The enzyme was inhibited by PCMB and 8-azaguanine.
在巨大芽孢杆菌中发现了一种催化各种蝶啶水解脱氨反应的蝶啶脱氨酶，并从细菌提取物中进行了部分纯化。其比活性比粗提物提高了90倍。最适pH约为7.3，6-羧基蝶啶的Km值为1.3 mM。通过凝胶过滤估计该酶的分子量约为110,000。该酶将蝶啶、6-羧基蝶啶、生物蝶呤、6-甲基蝶啶、7-甲基蝶啶、黄蝶呤、6-羟甲基蝶啶、异咯嗪蝶呤、异异咯嗪蝶呤、叶酸和6,7-二甲基蝶啶脱氨生成相应的鲁米诺嗪，而鸟嘌呤、7-羧基蝶啶、白蝶呤、异黄蝶呤和6-甲基异黄蝶呤不作为底物。该酶受到对氯汞苯甲酸和8-氮杂鸟嘌呤的抑制。
