Stöhrer G, Brown G B
Biochemistry. 1976 Jun 29;15(13):2772-5. doi: 10.1021/bi00658a010.
A major product of the reaction of L-tyrosine (I) with the activated oncogen 3-acetoxyxanthine (II) at neutral pH has been characterized as 8-xanthinyl-4'-O-tyrosine (III). A similar product is formed with tyrosylglycine. Another major product was the hydantoin of tyrosine. 8-Xanthinyl-4'-O-tyrosine is hydrolyzed in acid to yield tyrosine and uric acid but is stable in base. The synthesis of 8-phenoxyxanthine is also described. A metabolite identical with III in several chromatographic systems was found in the urine of two rats after administration of radioactive 3-hydroxyxanthine. This represented about 0.05% of the urinary radioactivity.
L-酪氨酸（I）与活化致癌基因3-乙酰氧基黄嘌呤（II）在中性pH条件下反应的一种主要产物已被鉴定为8-黄嘌呤基-4'-O-酪氨酸（III）。酪氨酸甘氨酸也形成了类似的产物。另一种主要产物是酪氨酸的乙内酰脲。8-黄嘌呤基-4'-O-酪氨酸在酸性条件下水解生成酪氨酸和尿酸，但在碱性条件下稳定。文中还描述了8-苯氧基黄嘌呤的合成。给两只大鼠注射放射性3-羟基黄嘌呤后，在其尿液中发现了一种在几种色谱系统中与III相同的代谢物。这约占尿放射性的0.05%。
