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26 terms

Protein Metabolism

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Essential AA (9)
Lys, Thr, Trp, Met, Ile, Leu, Val, Phe, His, Arg*
Non-Essential (11)
Ser, Gly, Cys, Ala, Asp, Asn, Arg, Glu, Gln, Pro (from Glucose); Tyr (from Phe)
Transamination RXNs (3)
Pyruvate to Alanine; a-KG to Glu; OAA to Asp; require PLP
Gly & Ser Synthesis
Phosphoglycerate from glycolysis to Serine / Gly
Cys Synthesis
Met donates S and Serine donates N & C
Tyr Synthesis
Phe to Tyr; BH4 cofactor & enzyme PAH; PKU disease = no PAH enzyme activity = build up of Phe in blood & Phenolic Pyruvate
Asn Synthesis
Derivative of Asp; Gln donates amide group
Synthesis of Glu, Gln, Pro, Arg
Formed from a-KG; Glu is precursor
Glucogenic Essential
Val, Thr, Met, His; can produce pyruvate or intermediates of the TCA cycle
Glucogenic Non-Essential
Ala, Arg, Asn, Asp, Cys, Glu, Gln, Gly, Pro, Ser
Glucogenic & Ketogenic (5)
Ile, Thr, & Phenolic (Phe, Trp, Tyr); produce acetyl CoA or ketone bodies and cannot produce OAA which is necessary for gluconeogenesis
Ketogenic (2)
Lys, Leu
Converted to Acetoacetate
Leu, Lys, Phe, Trp, Tyr
Converted to Acetyl CoA
Ile, Thr
Converted to Pyruvate
Ala, Cys, Gly, Ser, Thr, Trp
Converted to Glu then aKG
Gln, Pro, His, Arg
Converted to Succinyl CoA
Ile, Met, Thr, Val
Converted to Fumarate
Phe & Tyr
Converted to OAA
Asn, Asp
BCAA
Val, Ile, Leu; greatest potential for E use in muscle; make up 25% of protein; Leu increases insulin; Ile forms hemoglobin; Val
BCAA Degradation Step 1
Transamination = a-KG converts (Muscle)
BCAA Degradation Step 2
a-Keto groups undergo oxidative decarboxylation by a-keto acid dehydrogenase (Liver)
Val Degradation Products
FADH2, NADH, Gluconeogenic
Ile Degradation Products
NADH, both Gluco & Keto
Leu
FADH2, NADH, Keto
MSUD
maple syrup disease; a-keto acid dehydrogenase enzyme is defective in liver so you get a lot of build up of Glutamate & Glutamine