title: The activity of arylsulfatase A and B on tyrosine O-sulfates.
abstract: L-Tyrosine O-sulfate was hydrolyzed by pure human arylsulfatase A (arylsufate sulfohydrolase, EC 3.1.6.1). The rate of hydrolysis was 1/20 of the rate with nitrocatechol sulfate, but was comparable to the rate with cerebroside sulfate. The reaction was optimal at pH 5.3--5.5 and displayed zero order kinetics with time and enzyme concentration. The Km was about 35 mM. The enzyme showed no stereospecificity and hydrolyzed D-tyrosine O-sulfate with Km and V similar to those for the L-isomer. Arylsulfatase B was less than 5% as effective as arylsulfatase A in catalyzing the hydrolysis of the tyrosine sulfates. The daily urinary excretion of tyrosine sulfate by a patient with metachromatic leukodystrophy (arylsulfatase A deficiency) was comparable to the excretion by control subjects. The biological relevance of the tyrosine sulfatase activity of arylsulfatase A remains uncertain.
mesh_terms: D002553:Cerebroside-Sulfatase / Q000172:deficiency / Q000652:urine*; D002648:Child; D002803:Chondro-4-Sulfatase / Q000378:metabolism*; D005260:Female; D006801:Humans; D007700:Kinetics; D007966:Leukodystrophy, Metachromatic / Q000201:enzymology / Q000652:urine; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D013379:Substrate Specificity; D013429:Sulfatases / Q000378:metabolism* / Q000652:urine*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000652:urine
chemical_list: C005662:tyrosine O-sulfate; D014443:Tyrosine; D013429:Sulfatases; D002553:Cerebroside-Sulfatase; D002803:Chondro-4-Sulfatase