The HAO1 protein is a (S) -2-hydroxyacid oxidase with broad substrate specificity that facilitates glycolate oxidation. This activity produces glyoxylic acid, a key precursor for glycine synthesis. HAO1 Protein, Human (Trx-His) is the recombinant human-derived HAO1 protein, expressed by E. coli , with N-Trx, N-6*His labeled tag.