《生物化学》课程PPT教学课件（留学生）Chapter 21 Amino acids - disposal of nitrogen

BIOCHEMISTRYANDMOLECULARBIOLOGYChapter 21Amino acids:disposal of nitrogenDepartmentof Biochemistry and Molecular Biology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY Chapter 21 Amino acids: disposal of nitrogen

BIOCHEMISTRYANDMOLECULARBIOLOGY1.overviewAmino acids contain nitrogen, carbon, hydrogenand oxygenatoms.Removal of the a-amino groups by transaminationand oxidative deamination, forming ammonia andthe a- ketoacids.Department of Biochemistry and Molecular Biology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY ➢Amino acids contain nitrogen, carbon, hydrogen and oxygen atoms. ➢ Removal of the α-amino groups by transamination and oxidative deamination, forming ammonia and the α- ketoacids. 1. overview

BIOCHEMISTRYANDMOLECULARBIOLOGYtransaminationRR.RR2转氨酶CO=0H-C-NH+H-CNH+AminotransferaseCOOHCOOHCOOHCOOHoxidativedeaminationNHNH,Glutamate服外基医已HO可基疾大内本dehydrogenaseCH-COOHL谷氨酸脱氢酶、C-COOHC-COOH+NH城，基摩-HO2轻婚基度特的（CH）-COOHNADNADH+HH+（CH）2-COOH(CH）-COOH饿丙公谷氨酸glutamateα-酮成二酸a-ketoglutarateDepartment of BiochemistryandMolecularBiology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY Aminotransferase Glutamate dehydrogenase glutamate α-ketoglutarate transamination oxidative deamination

BIOCHEMISTRYANDMOLECULARBIOLOGY1.overviewa- ketoacids are converted to common intermediatesof energy producing metabolic pathways Some specialized products that are derived fromamino acids.Department of Biochemistry and Molecular Biology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY ➢α- ketoacids are converted to common intermediates of energy producing metabolic pathways. ➢ Some specialized products that are derived from amino acids. 1. overview

出BIOCHEMISTRYANDMOLECULARBIOLOGY1.overview A portion of the free ammonia is excreted in the urine.Most ammonia is used in the synthesis of urea.Department ofBiochemistryandMolecular Biology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY ➢ A portion of the free ammonia is excreted in the urine. ➢ Most ammonia is used in the synthesis of urea. 1. overview

北BIOCHEMISTRYANDMOLECULARBIOLOGY2.Overall nitrogen metabolism> Amino acid catabolism is part of the larger processof whole body nitrogen metabolism. Nitrogen entersthe body in a variety of compounds present in the food,the most important being amino acids contained indietary protein.Department ofBiochemistry and Molecular Biology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY ➢ Amino acid catabolism is part of the larger process of whole body nitrogen metabolism. Nitrogen enters the body in a variety of compounds present in the food, the most important being amino acids contained in dietary protein. 2.Overall nitrogen metabolism

Essential amino acidsBeans(richGrains Crich ininlysine)methionine)MilkPastaefagioli (pasta andbeans,ahealthyItaliansouptiff13.mov

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY

BIOCHEMISTRYANDMOLECULARBIOLOGY2.Overall nitrogen metabolism> Nitrogen leaves the body as urea, ammonia, andother products derived from amino acid metabolismThe role of body proteins in these transformationsraises two important concept: the amino acid pooland protein turnover.Department ofBiochemistry and Molecular Biology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY ➢ Nitrogen leaves the body as urea, ammonia, and other products derived from amino acid metabolism. The role of body proteins in these transformations raises two important concept: the amino acid pool and protein turnover. 2.Overall nitrogen metabolism

H2N-C-NH2HUreaAmmoniaUricacidExcreted Forms of Nitrogen

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY

大BIOCHEMISTRYANDMOLECULARBIOLOGY2.Overall nitrogen metabolismA. Amino acid poolAmino acids released by hydrolysis ofdietary or tissue protein mix with other freeamino acids distributed throughout the bodyand collectively constitute the amino acid poolDepartment of Biochemistry and Molecular Biology,MedicineSchool

Department of Biochemistry and Molecular Biology, Medicine School BIOCHEMISTRY AND MOLECULAR BIOLOGY 2.Overall nitrogen metabolism A. Amino acid pool Amino acids released by hydrolysis of dietary or tissue protein mix with other free amino acids distributed throughout the body, and collectively constitute the amino acid pool