作者:Motoo TSUSUÉ
DOI:10.1093/oxfordjournals.jbchem.a129526
日期:1971.1
Sepiapterin deaminase catalyzes the hydrolysis of sepiapterin to xanthopterin-B2 and ammonia. The enzyme was highly purified from the extract of the larval integument of the silkworm mutant, “lemon.” The enzyme has an optimum pH at 8.0 and the Km value for sepiapterin was found to be 5.9 × 10−4 M. The enzyme is specific for sepiapterin, and isosepiapterin is less effectively deaminated. Other pteridines tested, such as 2-amino-4-hydroxypteridine, xanthopterin and biopterin inhibit the deaminase activity. The stoichiometry of the deaminase reaction was established from balance studies. The enzyme is widely distributed in the larval tissues of this silkworm mutant, however, the biological role of the enzyme remains unknown.
Sepiapterin脱氨酶催化sepiapterin水解为xanthopterin-B2和氨。该酶是从蚕突变体“lemon”幼虫外皮的提取物中高度纯化的。该酶的最佳pH值为8.0,sepiapterin的Km值为5.9×10-4M。该酶对sepiapterin具有特异性,异sepiapterin的脱氨作用较弱。其他蝶啶类化合物,如2-氨基-4-羟基蝶啶、黄蝶啶和生物蝶啶,抑制脱氨酶活性。通过平衡研究确定了脱氨酶反应的化学计量。该酶广泛分布于该蚕突变体的幼虫组织中,但其生物学作用尚不清楚。