第31章 氢基酸及女重要铛 生物的生物合成
第31章 氨基酸及其重要衍 生物的生物合成
一、概论 型 (一)氨的来源 6 reduction by some anaerobic bacteria. most plants Amino acids and other reduced synthesis in nitrogen-carbon plants and compounds microorganisms degradation by animals and microorganisms Nitrate Ammonia NO3 3 NH denitrification nitrogen fixation by some bacteria (e.g.,Klebsiella Azotobacter,Rhizobium) nitrification nitrification by soil bacteria by soil bacteria e.g..Nitrobacter) Nitrite (e.g.,Nitrosomonas) NO2
一、概论 （一）氨的来源
Glucose (二)碳骨架的来源 Glucose 6-phosphate Ribose 5- phosphate Histidine Erythrose 4- 3-Phosphoglycerate Serine phosphate Glycine Phosphoenolpyruvate Cysteine Tryptophan Alanine Phenylalanine Pyruvate Valine Tryosine Leucine Oxaloacetate a-Ketoglutarate Aspartate Glutamate Asparagine Methionine Glutamine Threonine Proline LvsIe Arginine Isoleucine
（二）碳骨架的来源
4C0A+ (三)生物固氮 4 pyruvate 4 accCoA Be 8 Ferredoxin or 8 Ferredoxin or 8 flavodoxin 8 flavodoxin (oxidized) (reduced) 8 Dinitrogenase 8 Dinitrogenase reductase reductase (reduced) (oxidized) 16 ATP 16ADP +16P图 8 Dinitrogenase 8 Dinitrogenase reductase (reduced) reductase (oxidized +16ATP +16ATP 红色为固氮菌类菌体，蓝色为类菌 体周膜，黄色和绿色为被感染细胞 Dinitrogenase Dinitrogenase (oxidized) (reduced) 的细胞核。 8e 2NH H2 2H+
（三） 生物固氮 红色为固氮菌类菌体，蓝色为类菌 体周膜，黄色和绿色为被感染细胞 的细胞核
(a】 (b) COOH CHOH-CHOPO COOH HC H.C COOH HOOC F COOH 硝酸盐同化酶结 构域的序列构成 COOH COOH Sequence Organization of the Nitrate Assimilation Enzymes 硝酸盐和亚硝酸盐还原酶 Plant and Fungal Nitrate Reductases 的辅基：(a)硝酸盐还原酶 (~200 kD homodimers） 的钼铺因子，钼的载体为 N-term MoCo/NO hinge cytochrome b hinge FAD NAD(P)H 喋啉衍生物。(b)是卟啉 112 482 542 620 656 787 917 的衍生物，羧基可以作 为氢离子的供体，将亚硝 Plant Nitrite Reductases (63 kD monomers) 酸盐还原为铵盐。 e donor FeS-siroheme/NO 473 518566 Fungal Nitrite Reductases (-250 kD homodimers) FAD NAD(P)H Cys-rich FeS-siroheme/NO2 2660 183 215 496 600 715 763 1176
硝酸盐同化酶结 构域的序列构成 硝酸盐和亚硝酸盐还原酶 的辅基:(a)硝酸盐还原酶 的钼辅因子，钼的载体为 喋啉衍生物。(b)是卟啉 的衍生物， 羧基可以作 为氢离子的供体，将亚硝 酸盐还原为铵盐