Glycogenic Amino Acids
- Arginine
- Glutamine
- Histidine
- Proline
- Isoleucine
- Methionine
- Threonine
- Valine
- Phenylalanine
- Asparagine
- Aspartate
- Alanine
- Cysteine
- Glycine
- Serine
- Tryptophan
Ketogenic Amino Acids
- Isoleucine
- Leucine
- Threonine
- Tryptophan
- Lysine
- Phenylalanine
- Tyrosine
Name a common function in amino acid catabolism.
One-carbon transfers
One-carbon transfer enzyme cofactors
- Biotin
- Tetrahydrofolate
- S-adenosylmethionine
Biotin Transfer
Transfers CO2, carbon in its most oxidized state
Tetrahydrofolate Transfer
Transfers carbon in intermediate oxidized states and -CH3 groups, the most reduced state
S-adenosylmethionine Transfer
Transfers -CH3 groups
Tetrahydrofolate
- derivative of folate (vitamin)
- the one carbon group undergoing transfer is bonded to N-5 or N-10 and is carried as a methyl, methylene, methanol, formyl or formimino group.
S-adenosylmethinonine
- preferred cofactor for biological methyl group transfers
- 1000 times more reactive then the N-5 group of tetrahydrofolate
- derived from ATP and methionine
Six amino acids degraded to pyruvate
- A, C, G, S, T and W
- converted directly to pyruvate
- can then be converted to oxaloacetate or acetyl-CoA
T and G’s conversion to pyruvate
facilitated by tetrahydrofolate
Seven amino acids degraded to acetyl-CoA
- Portions of W, K, F, Y, L, I and T
- ketogenic amino acids
- end result of acetyl-CoA can be ketone bodies
F and Y conversion to fumarate
other portions of F and Y are converted to fumarate to feed TCA or gluconeogenesis
Five amino acids converted to α- ketoglutarate
- Portions of P, E, Q, R and H
- H is the only amino acid that requires a cofactor, in the final step a carbon is passed to tetrahydrofolate
Four amino acids are converted to succinyl-CoA
- Portions of M, I, T and V
- ultimately produce propionyl-CoA which is converted to succinyl-CoA
- M donates its -CH3 to S-adenosylmethionine
Propionyl-CoA to succinyl-CoA
converted via odd chain fatty acid oxidation
Branched chain amino acids
- In muscle, adipose, kidney and brain L, I and V are oxidized as fuels
- aminotransferases remove the amino group and α- kept acid dehydrogenase complexes the oxidative decarboxylation and formation of acyl-CoA derivatives
N and G converted to oxaloacetate
-converted to oxaloacetate and enter the citric acid cycle and gluconeogenesis
Amino acid degradation to reducing equivalents
the degradation of amino acids ultimately results in the generation of reducing equivalents (NADH and FADH2) which feed oxidative phosphorylation
