AA Catabolism

Essential AAs = Amino acids we CANNOT synthesize on our own; we must acquire them from our diet (= are an “essential” part of our diet) Non-Essential AAs = Amino acids we CAN synthesize on our own (= are a “non-essential” part of our diet, we don’t need to get them from our food)

There are 9 essential AAs: 1) Tryptophan 2) Threonine 3) Histidine 4) Valine 5) Isoleucine 6) Phenylalanine 7) Methionine 8) Leucine 9) Lysine

Try THis VIP MaLL (Careful!! P = Phenylalanine!)

There are 11 non-essential AAs: 1) Alanine 2) Arginine 3) Aspartate 4) Asparagine 5) Cysteine 6) Glycine 7) Glutamine 8) Glutamate 9) Proline 10) Serine 11) Tyrosine (All those NOT in “Try THis VIP MaLL”

1) Entry into the ketone body pathway (conversion to acetyl-coA) 2) Entry into the TCA cycle (conversion to TCA intermediate)

Ketogenic AAs = Amino acids whose carbon skeletons can be converted into acetyl-CoA or acetoacetyl-CoA to then enter ketone body production pathways Glucogenic AAs = Amino acids whose carbon skeletons can be converted into TCA cycle intermediates to continue into the TCA cycle to make OAA and enter gluconeogenesis!

Ketogenic = Total SEVEN (2 solely, 5 mixed) Glucogenic = Total EIGHTEEN (13 solely, 5 mixed) –> 2 AAs are ONLY ketogenic –> 13 AAs are ONLY glucogenic –> 5 AAs are BOTH ketogenic + glucogenic

13 of them: 1) Alanine 2) Arginine 3) Asparagine 4) Aspartate 5) Cysteine 6) Glycine 7) Glutamine 8) Glutamate 9) Histidine 10) Methionine 11) Proline 12) Serine 13) Valine

2 of them: 1) Lysine 2) Leucine (The 2 Ls!)

“These don’t FITTT in either category” (5 of them) 1) Phenylalanine (F) 2) Isoleucine (I) 3) Tyrosine (T) 4) Threonine (T) 5) Tryptophan (T)

1) PLP = Transamination rxns 1 Carbon transfer rxns: 2) Biotin 3) adoMet (adenosylmethionine) 4) THF (Tetrahydrofolate)

Biotin, adoMet, THF

Vitamin B7 (biotin)

Solely CO2! = most oxidized form of carbon!

1) Biotin binds to carboxylase enzyme active site via a lysine residue that forms an amide linkage with biotin’s long COO- arm! 2) Once anchored, the carboxylase enzyme phosphorylates bicarb using ATP to activate it 3) Once activated, one of biotin’s nitrogens attacks the bicarb, displacing the Pi grp and forming a bond with CO2! 4) The biotin typically then swings over to the oppositve active site and donates this CO2 group to a substrate that comes in! (carboxylating the substrate)

1) Biotin carboxylase = Carboxylates the biotin itself (adds CO2) 2) Carboxyl transferase = Transfers CO2 grp from biotin to substrate

Vitamin B9 (folate)

1) Methyl (-CH3) 2) Methylene (-CH2-) (-CH2OH) 3) Methenyl (-CH=) (-CH=O)

Bound to either: 1) N5 2) N10 3) N5 AND N10 (N5, N10)

Typically comes from SERINE! (CAN also come from glycine or formate)

Adenosine + methionine

METHYL (only methyl!)

The methyl grp coming off of the suflur from methionine

N5-methyl-THF! (only known use for this cofactor actually!)