NH3 CO2.ATP Aspartate a-Ketoglutarate Glutamate Carbamoyl phosphate Asparagine Glutamate Glutamine Arginine Other Purine nucleotides, pyrimidines, cytidine nucleotides. amino urea acids amino sugars, tryptophan,histidine
(二)氨基酸的脱羧 NH. NH NH HO CH -CH-C0o O0C-CH,-CH,-CH-C00 CH-COO Tyruaine Tetrahydrobiopterin Tryptophan 0 ‘Dihydrobiopteri N HO NH. OOC-CH,-CH,-CH, →B0 Dihydrobicpterin HO -CH:-CH-C0O (GABA Dopa NH. -CH-Coo NHo HO CH2-CH-COO HO NH. -CH2-CH 日过ine →C0 NH 0 →Hu0 HO CH:-CH. HO NH. HO CH-CH. N NH rotonin OH 压istamine Norepinephrine Ho H:N-CH HO CH-CH: OH
（二）氨基酸的脱羧
(三) 氨的去向 ☆谷氨酰胺的合成 谷氨酸和氨生成无毒的谷氨酰胺经血液运输到肾 脏再分解成谷氨酸和氨 。 Nitrogen can also be transported as glutamine.Glutamine synthetase catalyzes the synthesis of glutamine from glutamate and NH4 in an ATP- dependent reaction: NH+glutamate+ATP Glutamine yntheta glutamine ADP P
（三）氨的去向 ☆谷氨酰胺的合成 谷氨酸和氨生成无毒的谷氨酰胺经血液运输到肾 脏再分解成谷氨酸和氨 • Nitrogen can also be transported as glutamine. Glutamine synthetase catalyzes the synthesis of glutamine from glutamate and NH4 + in an ATPdependent reaction:
☆谷氨酰胺的合成 NHa OOC-CH2-CH2-CH-COO L-Glutamate ATP glutamine synthetase →ADP NH3 CH2-CH2-CH-COO y-Glutamyl phosphate NHi glutamine synthetase →P NHg C-CH2-CH2-CH-COO H2N L-Glutamine glutaminase H2O (liver mitochondria) →NHt→→Urea NH3 CC-CH2-CH2-CH-COO L-Glutamate
☆谷氨酰胺的合成
☆鸟氨酸循环(Urea Cycle) 肝脏中二分子氨和一分子二氧化碳生成一 分子尿素的环式代谢途径 The nitrogens of glutamine can be converted into urea in the liver
☆鸟氨酸循环 (Urea Cycle) 肝脏中二分子氨和一分子二氧化碳生成一 分子尿素的环式代谢途径 • The nitrogens of glutamine can be converted into urea in the liver