Histidine a basic amino acid formed only rarely in proteins . it is formed from atp and 5 - phosphoribosyl pyrophosphate in a complex biosynthetic pathway . glutamate is an intermediate in its breakdown 组氨酸:是蛋白质中少有的一种碱性氨基酸。由atp和5 -磷酸核糖基焦磷酸盐通过复杂的生物合成途径合成。在其降解过程中可形成谷氨酸。