“…Seven groups of these genes and proteins were identified, including ARS group 5 for a single human ARSK gene, which encodes a distinct 526 amino acid sequence enzyme and shares <27% sequence identities with other human arylsulfatases. This is in contrast to the sequence identities observed for other human enzyme ARS groups: Group 1 (ARSA, ARSG and GALNS) (33-39% identical); group 2 (ARSB, ARSI and ARSJ) (54-59%) [2]; group 3 (ARSD, ARSE, ARSF, ARSH and STS) (57-64%) [3]; and group 4 ARS sequences (SULF1, SULF2 and GNS) (42-67%) [5]. Groups 6 (SGSH) and 7 (IDS) [4] enzymes, however, exhibited distinct amino acid sequences which were 22% and 26% identical, respectively, with the human ARSK amino acid sequence ( Table 2).…”