1-Aminocyclopropane-1-Carboxylate Synthase (ACCS)

PHACS expressed in yeast contained bound pyridoxal-5-prime-phosphate and catalyzed the deamination of L-vinylglycine. It did not catalyze the synthesis of 1-aminocyclopropane-1-carboxylate, the major activity of plant ACS.

The deduced 501-amino acid protein has a calculated molecular mass of 58 kD. Bioinformatic analysis indicated that PHACS is a member of the alpha family of pyridoxal-5-prime-phosphate enzymes. PHACS contains overlapping aminotransferase I and beta-eliminating lyase domains, and it shares structural similarity with aspartate aminotransferase, tyrosine aminotransferase , and enzymes that catalyze beta-elimination reactions on amino acids. Analysis of available ESTs suggested that PHACS is expressed in a wide range of tissues.