de Sousa Júnior J F, Nader H B, Dietrich C P
Departamento de Bioquimica, Universidade Federal do Rio Grande do Norte, Natal RN, Brazil.
J Biol Chem. 1990 Nov 25;265(33):20150-5.
A sulfatase acting upon chondroitin sulfate polymers, free of beta-glucuronidase and beta-N-acetylhexosaminidases, was isolated from extracts of the mollusc Anomalocardia brasiliana. The enzyme totally desulfates both chondroitin 4- and 6-sulfates without concomitant depolymerization of the compounds. It has no activity upon heparan sulfate, heparin, dermatan sulfate, and chondroitin sulfate disaccharides. It shows a pH of 5.0 and a temperature of 37 degrees C for optimum activity with a Km of 4 x 10(-5) M. The sulfatase is inhibited by sulfate and phosphate ions and HgCl2. The latter inhibition is reverted by sodium tetrathionate. Contrary to the sulfatases described so far the enzyme is activated by the lactone of D-saccharic acid when in the presence of beta-glucuronidase and beta-N-acetylgalactosaminidase. Several experiments indicate that the sulfatase is the first enzyme in the sequential degradation of chondroitin sulfate in the mollusc. This differs from the pathway of degradation of this compound in vertebrates and bacteria.
从巴西偏盖蛤软体动物提取物中分离出一种硫酸酯酶，该酶作用于硫酸软骨素聚合物，不含β-葡萄糖醛酸酶和β-N-乙酰己糖胺酶。该酶能使硫酸软骨素4-硫酸酯和6-硫酸酯完全脱硫，且不会使化合物同时解聚。它对硫酸乙酰肝素、肝素、硫酸皮肤素和硫酸软骨素二糖无活性。其最适活性的pH值为5.0，温度为37℃，米氏常数为4×10⁻⁵M。该硫酸酯酶受到硫酸根离子、磷酸根离子和HgCl₂的抑制。后一种抑制作用可被连四硫酸钠逆转。与迄今为止描述的硫酸酯酶不同，当存在β-葡萄糖醛酸酶和β-N-乙酰半乳糖胺酶时，该酶被D-糖二酸内酯激活。多项实验表明，该硫酸酯酶是软体动物中硫酸软骨素顺序降解的第一种酶。这与脊椎动物和细菌中该化合物的降解途径不同。
