5  α-Amino Acids In Water: A Review of VCD and ROA Spectra  
141
Table A2 metabolism of amino acids
AA
Skeleton catabolism Biosynthesis of the other AA
other metabolites
Alanine
glucogenic
Pyruvate → … → glucose [A24]
Arginine
glucogenic
ornithine [A30]
Nitric oxide [A29, A30]
urea [A30]
Polyamines [A30]
Creatine [A30]
Agmatine (a novel neurotransmitter in brain involved in learning and memory
and exhibiting anticonvulsant, antinociceptive, anxiolytic and antidepressant-like actions. [A32]
Asparagine
glucogenic
Aspartate [A3]
Aspartic acid
glucogenic
Asparagine homoserine, threonine,
isoleucine, methionine, lysine
[A3, A10, A11, A18, A21]
Inosine (the precursor to the purine bases) [A9]
Cysteine
glucogenic
taurine (essential for normal brain and skeletal muscle functioning) [A33]
glutamine
glucogenic
glutamate [A8]
Nitrogen donation for the synthesis of purines [A9]
glutamic acid
glucogenic
glutamine arginine, proline [A8,
A2, A16]
gABA (inhibitory neurotransmitter) [A27]
glycine
glucogenic
donation of C
2
N subunit for the synthesis of purines [A9]
d-aminolevulinic acid (the key precursor to porphyrins) [A9]
histidine
glucogenic
Trans-urocanic acid → glutamic acid (in UV light, the urocanic acid undergos 
trans - cis isomerisation and both isomers, of absorption spectra overlapping
to a large extent those of nucleic acids, forms a natural sun screen for the
skin.) [A34]
Carnosine (ph-buffering
role in muscles for overcoming muscle fatigue, antioxidant properties, metal-chelator) [A35]