No abstract

Arylsulphatase activity was identified in cultures of the marine bacterium Alteromonas carrageenovora, using methylumbelliferyl sulphate as substrate. In contrast with most other microbial arylsulphatases, arylsulphatase production in A. carrageenovora was not repressed by sulphate. The structural gene of arylsulphatase (atsA) was cloned and sequenced. An ORF of 984 bp was found, specifying a primary translation product of 328 amino acids with a molecular mass of 35797 Da. Arylsulphatase was partially purified from cell extracts of both A. carrageenovora and recombinant Escherichia coli. Both the recombinant and native enzymes exhibited a pl of 55, a Michaelis constant for methylumbelliferyl sulphate of 68 pM, and a molecular mass of approximately 35000 Da in SDS-PAGE analysis. Secondary structure comparisons using hydrophobic cluster analysis suggest functional analogies between the arylsulphatase of A. carrageenovora, #at of Mycobacterium leprae and a 33.5 kDa protein from Porphymmonas gingivalis. It is speculated that these proteins are all glycosulphohydrolases, involved with desulphatation of sul pha ted pol ysaccha rides.