Arylsulfatase B (N-acetylgalactosamine-4-sulfatase, chondroitinsulfatase, chondroitinase, acetylgalactosamine 4-sulfatase, N-acetylgalactosamine 4-sulfate sulfohydrolase, EC 3.1.6.12) is an enzyme associated with mucopolysaccharidosis VI (Maroteaux–Lamy syndrome). Arylsulfatase B is among a group of arylsulfatase enzymes present in the lysosomes of the liver, pancreas, and kidneys of animals. The purpose of the enzyme is to hydrolyze sulfates in the body. ARSB does this by breaking down glycosaminoglycans (GAGs), which are large sugar molecules in the body. ARSB targets two GAGs in particular: dermatan sulfate and chondroitin sulfate.Over 130 mutations to ARSB have been found, each leading to a deficiency in the body. In most cases, the mutation occurs on a single nucleotide in the sequence. An arylsulfatase B deficiency can lead to an accumulation of GAGs in lysosomes, which in turn can lead to mucopolysaccharidosis VI. Used as a pharmaceutical drug, the enzyme is known under the International Nonproprietary Name galsulfase and is sold under the brand name Naglazyme. Galsulfase was approved for medical use in the United States in May 2005 and in  European Union in January 2006. Galsulfase is indicated for long-term enzyme-replacement therapy in people with a confirmed diagnosis of mucopolysaccharidosis VI (MPS VI; N-acetylgalactosamine-4-sulfatase deficiency; Maroteaux-Lamy syndrome). Structure
The primary structure of Escherichia coli  arylsulfatase B contains a primary sequence of 502 amino acids. Its secondary structure is quite complex, containing numerous alpha helices (20 total containing 138 residues) and beta sheets (21 strands total containing 87 residues). The functional enzyme is believed to be a homo tetramer.
Crystalluria refers to crystals found in the urine when performing a urine test. Crystalluria is considered often as a benign condition and as one of the side effects of sulfonamides and penicillins. The main reason for the identification of urinary crystals is to detect the presence of the relatively few abnormal types that may represent a disease. Clinical significance
It can be an indication of urolithiasis. It may be relevant when there is presence of specific abnormal types of crystals (cystine, cholesterol, leucine, tyrosine, etc.) and that may be a sign of metabolic or liver disorders such as cystinuria. It leads to formation of stones. References


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