Glutamine
In human blood, glutamine is the most abundant free amino acid.
Alanine
Alanine (symbol Ala or A) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated form, −NH, under biological conditions), an α-carboxylic acid group (which is in the deprotonated form, −COO, under biological conditions), and a side chain methyl group, making it a nonpolar, aliphatic amino acid. It is non-essential in humans: because the body can synthesize it, it does not need to be present in the diet. It is encoded by all codons starting with GC (GCU, GCC, GCA, and GCG).