tailieunhanh - Biochemistry, 4th Edition P85

Biochemistry, 4th Edition P85. Continuing Garrett and Grisham's innovative conceptual and organizing framework, "Essential Questions," BIOCHEMISTRY guides students through course concepts in a way that reveals the beauty and usefulness of biochemistry in the everyday world. Streamlined for increased clarity and readability, this edition also includes new photos and illustrations that show the subject matter consistently throughout the text. New end-of-chapter problems, MCAT practice questions, and the unparalleled text/media integration with the power of CengageNOW round out this exceptional package, giving you the tools you need to both master course concepts and develop critical problem-solving skills you can draw upon. | How Do Organisms Synthesize Amino Acids 803 a-pyrophosphate PRPP N1-5 -Phosphoribosyl-ATP H H nc 11 CH C- x I N CH2 HC NH h2coh H2O 2 NADH 2 NAD 3 H hc-N 11 CH C- CH2 HC NH COO- Histidine L-Histidinol H HC- 11 CH CVZ H A l-5 -Phosphoribosyl-AMP CH2 HC - NH CH2 O P n-Ketoglutarate Glutamate IIC 11 CH C I N CH2 C O ch2 O P L-Histidinol phosphate Imidazole acetol phosphate _M-5 -Phosphoribosylformimmo- 5-aminoimidazole-4-carboxamide ribonucleotide H iic-A. L H I N H C OH I H C OH CH2 O P Imidazole glycerol phosphate H C OH CH2 O P A1-5 -Phosphoribulosylformimino-5-aminoimidazole-4-carboxamide ribonucleotide O FIGURE The pathway of histidine enzymes are 1 ATP-phosphoribosyl transferase 2 pyrophosphohydrolase 3 phosphoribosyl-AMP cyclohydrolase 4 phosphoribosylformimino-5-aminoimidazole carboxamide ribonucleotide isomerase 5 imidazole glycerol phosphate synthase 6 imidazole glycerol-P dehydratase 7 L-histidinol phosphate aminotransferase 8 histidinol phosphate phosphatase and 9 histidinol dehydrogenase. 5-Aminoimidazole-4-carboxamide ribonucleotide To purine biosynthesis 804 Chapter 25 Nitrogen Acquisition and Amino Acid Metabolism Figure . Five carbon atoms from PRPP and one from ATP end up in histidine. Step 5 involves some novel chemistry The substrate phosphoribulosylformimino-5-aminoimidazole-4-carboxamide ribonucleotide picks up an amino group from the amide of glutamine in a reaction accompanied by cleavage and ring closure to yield two imidazole compounds the histidine precursor imidazole glycerol phosphate and a purine nucleotide precursor 5-aminoimidazole-4-carboxamide ribonucleotide AICAR . Note that AICAR as a purine nucleotide precursor can ultimately replenish the ATP consumed in reaction 1. Nine enzymes act in histidine s ten synthetic steps. Reactions 9 and 10 the successive NAD -dependent oxidations of an alcohol to an aldehyde and then to a carboxylic acid are catalyzed by the same dehydrogenase. How Does Amino .

• Sinh học
• Nền tảng của hóa sinh học
• trao đổi chất protein
• RNA trao đổi chất
• nguyên tắc của hóa sinh
• Axit amin
• công nghệ DNA