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。