The human asparaginase-like protein 1 hASRGL1 is an Ntn hydrolase with beta-aspartyl peptidase activity.
Herein we report the bacterial expression, purification, and enzymatic characterization of the human asparaginase-like protein 1 (hASRGL1). We present evidence that hASRGL1 exhibits beta-aspartyl peptidase activity consistent with enzymes designated as plant-type asparaginases, which had thus far been found in only plants and bacteria. Similar to nonmammalian plant-type asparaginases, hASRGL1 is shown to be an Ntn hydrolase for which Thr168 serves as the essential N-terminal nucleophile for intramolecular processing and catalysis, corroborated in part by abolishment of both activities through the Thr168Ala point mutation. In light of the activity profile reported here, ASRGL1s may act synergistically with protein l-isoaspartyl methyl transferase to relieve accumulation of potentially toxic isoaspartyl peptides in mammalian brain and other tissues.
Department of Chemical Engineering, University of Texas, Austin,Texas 78712, USA.
Jason R
JR
Cantor
Everett M
EM
Stone
Lynne
L
Chantranupong
George
G
Georgiou
D000581:Amidohydrolases / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D001215:Asparaginase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001324:Autoantigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis; D020134:Catalytic Domain; D004150:Dipeptidases / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D001324:Autoantigens; D004151:Dipeptides; D011994:Recombinant Proteins; D004150:Dipeptidases; C051396:beta-aspartyl peptidase; D000581:Amidohydrolases; C466840:ASRGL1 protein, human; C438834:N-terminal nucleophile hydrolase; D001215:Asparaginase