Biochemistry: The Chemical Reactions of Living Cells, Volume 2 - D. Metzler 1980

Types of reactions catalyzed by enzymes
Sulfate transfer

Although sulfuric acid esters (organic sulfates) do not play as central a role in METABOLISM as phosphoric acid esters, they are nevertheless widespread. Both oxygen-containing esters (R—O—SO^-₃, frequently referred to as O-sulfates¹⁾) and sulfamic acid derivatives (R—NH—SO^-₃, N-sulfates¹⁾) have been identified, with the latter occurring in mucopolysaccharides (such as heparin). Sulfate esters of mucopolysaccharides and Steroids are ubiquitous. Choline sulfate and ascorbic acid 2-sulfate are found in various Cells. Phenolic sulfate esters and many other organic sulfates have also been detected in urinary excretion products.

Sulfotransferases (including sulfokinases) transfer sulfo-ester groups to —O and —N of suitable acceptors (Reaction type 1.G in Table 7-1). The carrier is frequently a specialized "active sulfate"—3-phosphoadenosine-5'-phosphosulfate [Equation (11-4)]. However, transfer mediated by ascorbic acid 2-sulfate can also play a significant role [95, 96]. Sulfatases catalyze the Hydrolysis of sulfuric acid esters. The physiological importance of these Enzymes was demonstrated in The Study of a genetic metabolic disorder known as mucopolysaccharidosis III (Sanfilippo syndrome), which is characterized by the excessive excretion of heparan sulfate, presumably due to a deficiency of the corresponding specific sulfatase [97]. This disorder results in severe intellectual disability. Although an extensive literature is dedicated to sulfate-transferring enzymes [98], very few studies have been conducted using purified enzyme preparations.

¹⁾ Although these terms are widely used, they are somewhat inaccurate; it is actually the sulfuryl radical, rather than the sulfate group, that is attached to the oxygen and nitrogen atoms.