Protein and Amino Acid Metabolism

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Protein and Amino Acid Metabolism

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OutlineProtein and Amino Acid Metabolism

• 1. ????
• -??????????????????????????????????????????
• 2.Overview of Protein and Amino Acid Metabolism
• -Essential and Non-essential Amino Acids
• -Amino Acid Pool
• -Protein Turnover
• -Nitrogen Balance

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• 3. ??????????????????????????????
• 4. ?????????????????
• 5. ???????????????????
• -???????????????? ??????????????????,
• urea cycle
• - ???????????????? ??????????????????
• 6. ??????????????????????
• ????? non-essential amino acids

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• 7. ???????????????????????????????????????????
• -Tyrosine -Glycine, Arginine, SAM
• -Tryptophan -Polyamines
• -Glutamate -NO
• -Histidine -Heme and Bile pigments
• 8. Disorders related in amino acid metabolism

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I Overview of Protein and Amino Acid Metabolism
Dietary proteins
Digestion
Amino acids in blood
Membrane
Cell
Amino Acids
Proteins
Carbon
N-Compounds
Nitrogen
UreaN-waste
CO2H2O
Urine
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Overview of Nitrogen Metabolism
Marks DB, et.al. p.571, 1996
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(No Transcript)
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Essential and Non-essential Amino Acids
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Essential and Non-essential Amino Acids
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?????? ???????????????????????????????????????????
??????????? (???? ?? ?????????? ??????)
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??????????????????????????????????????????????????
??????????? ???? gliadin ?????????????????????
???????????? zein ????????????????????
???????????????????????? ?????????????????????
????????????????? ???????????????????
(gelatin) ?????????????????????????????????????? ?
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Amino Acid Pool
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metabolism ????????????????????
?????????????????????? -??????????????????????????
????? -????????????? (??????????) -???????
??? (???????????) metabolism ?????????????????????
??????????????????????????????????????????????????
???????????? ?????????????????????????????????????
?????????????? ????
amino acid pool
????????????????????? (protein turnover)
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Protein turnover

• Degradation
• denatured proteins
• abnormal proteins
• By
• Lysosome
• Ubiquitin /proteasome ATP
• Short half-life PEST sequence

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???????????????????????????? (Proteolysis of
endogenous protein)
???????????????????????????????????????? 1.
????????? denature 2. ???????????????????????
lysosome 3. Glucocorticoids ??????????????
???????????????????????????? 4. Excess thyroid
hormones ????? protein turnover 5. insulin
????????????? ???????????????????
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????????????????????????????
-????????????? -???????????? 30 ????-150
??????? -????????????????? ????? PEST sequence
(Pro, P Glu, E Ser, S Thr, T) -???????????????
?????????????????????????????????????
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Nitrogen Balance

• Positive
• Negative
• Kwashiokor
• Marasmus

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Major Pathways of Amino Acid Uses
Body protein
Protein synthesis
Proteolysis
UreaCO2H2O
Amino acid pool
Absorption
Biosynthesis of special molecules
Porphyrins
Creatine
Polyamines
Carnithine
Nucleotides
Hormones and neurotransmitter
Carnosine and anserine
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Digestion of Protein and Amino Acid Absorption
Marks DB, et.al. p.574, 1996
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Co-Transport Facilitated diffusion Active
Transport (????????? 5 ????????????????)
Marks DB, et.al. p.576, 1996
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Active Transport
Davidsons V., p.374, 1999
Cystinuria ??????--gt ??????? Cystine, Ornithine,
Arginine, Lysine ??????
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g-Glutamyl cycle
GSH synthetase
Mark DB , et.al. p.576, 1996
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Glutathione

• ???????????
• ??????? thiol
• ?????????????????????????? DNA, RNA, Eicosanoids
• reducing agent