同济大学：《细胞的生物化学》课程电子教案（课件讲稿）氨基酸代谢 Amino Acid Metabolism

Amino acid metabolism H3N- H R

COO H3N C H R _ + Amino acid metabolism

Amino acid consumption: (Protein-rich diet) Percentage of radiolabelled nitrogen found: 57%Urea 6%plasma protein 14%protein in liver 23%free amino acids in circulation

Amino acid consumption: (Protein-rich diet) Percentage of radiolabelled nitrogen found: 57% Urea 6% plasma protein 14% protein in liver 23% free amino acids in circulation

Protein uptake: Total protein: ~100 g day ~10kg gesamte Protein- synthese 300g Muskel: 75g Protein and sezerniert 50-70g amino acid Darm resorbiert 70-150g Leber: metabolism Albumin 12g freie70g Aminosauren Lymphocyten: Immunglobulin 2g88 Leukocyten in faces ~10g 20g888 Erythrocyten: Hamoglobin 8g Harn-N(als Protein) 20-70g via skin ~2g in urine ~30g

Protein uptake: ~ 100 g / day Total protein: ~ 10 kg Protein and amino acid metabolism in faces ~ 10 g in urine ~ 30 g via skin ~ 2 g

Amino acid metabolism Decarboxylation ● Deamination Transamination Urea cycle Pyruvate group a Ketoglutarate group Succinyl-CoA group Oxaloacetate group Fumarate oxaloacetate group Alanine acetoacetate group Acetyl-CoA acetoacetate group

Amino acid metabolism • Decarboxylation • Deamination • Transamination • Urea cycle • Pyruvate group • a Ketoglutarate group • Succinyl-CoA group • Oxaloacetate group • Fumarate / oxaloacetate group • Alanine / acetoacetate group • Acetyl-CoA / acetoacetate group

Amino acid decarboxylation NHs *H3N-C-H (biotin) CH2 R CO2 R biological amine

Amino acid decarboxylation COO H3N C H R _ + (biotin) CO2 NH3 CH2 R + biological amine

Formation of biological amines amino acid decarboxyl.product examples of functions aspartic acid B alanine coenzyme A cysteine cysteamine coenzyme A dihydroxy- dopamine neuro-transmitter phenylalanine glutamic acid y aminobutyric acid neuro-transmitter histidine histamine mediator in allergic reactions lysine cadaverine corpse venom ornithine putrescine polyamine metabolism serine ethanolamine phospholipids threonine aminopropanol vitamine B12 tyrosine tyramine uterus contraction tryptophane tryptamine probably hormon action hydroxy- serotonine neuro-transmitter tryptophane

amino acid decarboxyl. product examples of functions aspartic acid ß alanine coenzyme A cysteine cysteamine coenzyme A dihydroxy￾phenylalanine dopamine neuro-transmitter glutamic acid g aminobutyric acid neuro-transmitter histidine histamine mediator in allergic reactions lysine cadaverine corpse venom ornithine putrescine polyamine metabolism serine ethanolamine phospholipids threonine aminopropanol vitamine B12 tyrosine tyramine uterus contraction tryptophane tryptamine probably hormon action hydroxy￾tryptophane serotonine neuro-transmitter Formation of biological amines

Amino acid metabolism Decarboxylation Deamination Transamination Urea cycle ● Pyruvate group a Ketoglutarate group Succinyl-CoA group Oxaloacetate group Fumarate oxaloacetate group ● Alanine acetoacetate group Acetyl-CoA acetoacetate group

Amino acid metabolism • Decarboxylation √ • Deamination • Transamination • Urea cycle • Pyruvate group • a Ketoglutarate group • Succinyl-CoA group • Oxaloacetate group • Fumarate / oxaloacetate group • Alanine / acetoacetate group • Acetyl-CoA / acetoacetate group

amino acid deamination protein intra uptake cellular protein amino acids desamination a ketoacids NHa glucose amino citric acids acid nucleo- cycle tides metabolites CO2,H2O urea

amino acids protein uptake intra cellular protein a ketoacids NH4 + citric acid cycle amino acids, nucleo￾tides CO2, H2O urea metabolites glucose desamination amino acid deamination

Deamination of amino acids 1.oxidative deamination NADP NAD NADPH NADH COOH COOH HN=0 H30 COOH C=0 NHg Glutamat NAD H2O NH3 2-Oxoglutarat NADH

Deamination of amino acids 1. oxidative deamination

2.deamination by B elimination (Ser,Thr,Cys) COOH COOH PLPEN-C-H CH2 H20 OH serine PLP COOH COOH HN■C H20 COOH NHg CH PLP pyridoxalphosphate pyruvate

2. deamination by ß elimination (Ser, Thr, Cys) PLP = pyridoxalphosphate serine pyruvate