It has been shown that horse muscle acylphosphatase is inhibited by pyridoxal 5'-phosphate and that the inhibition is pH dependent, reversible and competitive with respect to substrate binding. Spectral analysis on the EI complex demonstrates the presence of a Schiff base. Reduction of the pyridoxal 5'-phosphate-inhibited enzyme with sodium borohydride, followed by amino acid analysis, produces a diminution of the free lysine peak and the appearance of a new peak corresponding to epsilon-pyridoxyllysine. The results suggest that there is at least one NH2-lysyl residue of horse muscle acylphosphatase at or near the active site of the enzyme.
Inhibition of horse muscle acylphosphatase by pyridoxal 5'-phosphate / G. Ramponi; G. Manao; G. Camici; G.F.White. - In: BIOCHIMICA ET BIOPHYSICA ACTA. - ISSN 0006-3002. - STAMPA. - 391:(1975), pp. 486-493. [doi:10.1016/0005-2744(75)90272-7]