label: (2S)-2-aminobutanoate + L-glutamate + ATP = gamma-L-glutamyl-(2S)-2-aminobutanoate + ADP + phosphate + H(+)
label_lc: (2s)-2-aminobutanoate + l-glutamate + atp = gamma-l-glutamyl-(2s)-2-aminobutanoate + adp + phosphate + h(+)