Recombinant human glycosylasparaginase catalyzes hydrolysis of l-asparagine

AbstractGlycosylasparaginase is a lysosomal amidase involved in the degradation of glycoproteins. Recombinant human glycosylasparaginase is capable of catalyzing the hydrolysis of the amino acid l-asparagine to l-aspartic acid and ammonia. For the hydrolysis of l-asparagine the Km is 3–4-fold higher and Vmax 1/5 of that for glycoasparagines suggesting that the full catalytic potential of glycosylasparaginase is not used in the hydrolysis of the free amino acid. l-Asparagine competitively inhibits the hydrolysis of aspartylglucosamine indicating that both the amino acid and glycoasparagine are interacting with the same active site of the enzyme. The hydrolytic mechanism of l-asparagine and glycoasparagines will be discussed