3bsqA Introduction

Sulfatases are enzymes that hydrolyze sulfate ester bonds of substrates. These are categorized as EC 3.1.6. in enzyme classifications. They all participate in metabolic processes, most of the family members are shown to contain a highly conserved cystine residue and a bivalent metal binding site. Majority of sulfatases are located in lysosomes with an acidic pH optima; however human steroid sulfatase is found in endoplasmic reticulums (ER) with a neutral pH potima. most of the sulfatases including Arylsulfatase A (ASA), Arylsulfatase B (ASB) and N-acetylgalactosamine-6-sulfatase (G6S) are water soluble.

The sulfatase in our focus is arylsulfatase K (ASK), where the crystal structure is been solves but no functional characterization is done to the date. In this experiment sequence conservation, structural similarity, other proteins that ASK is known to interact with, and the level of conservation of some key residues that may be involved in its catalytic activity were looked at; to determine the possible function of the ASK [[1]].

Function of some other sulfatases were found searching literature. ASA is a lysosomal enzyme which hydrolyzes cerebroside sulphate. ASB is also a lysosomal enzyme which hydrolyzes the sulphate ester group from N-acetylgalactosamine 4-sulphate group of dermatine sulphate. Arylsulfatase C is a microsomal membrane-bound enzyme hydrolyses 3-beta-hydroxysteroid sulfates which is also known as steroid sulfatase[[2]]. The range of substrates catalysed by sulfatases is diverse, including cerebroside sulfate, dermatan sulfate, heparan sulfate, heparin and keratan sulfate, and steroid sulfates [[3]]