Fluharty A L, Stevens R L, Goldstein E B, Kihara H
Biochim Biophys Acta. 1979 Feb 9;566(2):321-6. doi: 10.1016/0005-2744(79)90035-4.
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.
L-酪氨酸O-硫酸盐可被纯人芳基硫酸酯酶A（芳基硫酸酯硫酸水解酶，EC 3.1.6.1）水解。其水解速率是硫酸硝基邻苯二酚水解速率的1/20，但与硫酸脑苷脂的水解速率相当。该反应在pH 5.3 - 5.5时最佳，且随时间和酶浓度呈零级动力学。米氏常数（Km）约为35 mM。该酶无立体特异性，水解D-酪氨酸O-硫酸盐时的Km和V与L-异构体相似。芳基硫酸酯酶B在催化酪氨酸硫酸盐水解方面的效率不到芳基硫酸酯酶A的5%。一名异染性脑白质营养不良（芳基硫酸酯酶A缺乏）患者每日尿中硫酸酪氨酸的排泄量与对照受试者相当。芳基硫酸酯酶A的酪氨酸硫酸酯酶活性的生物学意义仍不确定。
