Recombinant human glycosylasparaginase catalyzes hydrolysis of l-asparagine

• Published in: FEBS letters 1997-07, Vol.412 (1), p.149-152
• Main Authors: Noronkoski, Tiina, Stoineva, Ivanka B., Petkov, Dimiter D., Mononen, Ilkka
• Format: Article
• Language: English
• Subjects: AGU; Ammonia - metabolism; Asn; Asp; AspAMC; Asparaginase; Asparagine - metabolism; Asparagine - pharmacology; Aspartic Acid - metabolism; Aspartylglucosylaminase - metabolism; aspartylglycosaminuria; Binding Sites; Binding, Competitive; carboxymethylcysteine; Catalysis; Chromatography, High Pressure Liquid; CmCys; GlcNAc-Asn; Glycosylasparaginase; high-performance liquid chromatography; HPLC; Humans; Hydrogen-Ion Concentration; Hydrolysis; l-asparagine; l-asparagine metabolism; l-aspartic acid; l-aspartic acid β-(7-amido-4-methylcoumarin); Lysosomal enzyme; N 4-(β-N-acetyl-d-glucosaminyl)-l-asparagine, 2-acetamido-1-l-β-aspartamido-1,2-dideoxy-β-d-glucose, aspartylglucosamine; phenylisothiocyanate; PITC; Recombinant Proteins - metabolism; SDS-PAGE; sodiumdodecylsulphate polyacrylamide gel electrophoresis
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(97)00761-8

Glycosylasparaginase 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 K m is 3–4-fold higher and V max 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.