Components and proteolytic processing sites of arylsulfatase B from human placenta.
Previous studies have shown that mature arylsulfatase B purified from human sources is composed of two non-identical chains with apparent molecular masses of 43 kDa and 8 kDa. Arylsulfatase B purified from human placenta in the present study, however, included another 7 kDa component that could be detected only by carbohydrate staining on reducing SDS-PAGE employing the Tris-Tricine system. The 43 kDa and 7 kDa components contained a carbohydrate moiety, but the 8 kDa one did not, as demonstrated by periodic acid-Schiff staining, Con-A lectin blotting, endo-glycosidase treatment and in vitro phosphorylation by UDP-N-acetylglucosamine: lysosomal enzyme N-acetylglucosamine 1-phosphotransferase. The purified arylsulfatase B migrated as a single polypeptide of 58 kDa on non-reducing SDS-PAGE, indicating that the three chains are linked by disulfide bonds. In order to determine the origin of the components, N-terminal sequencing of the isolated polypeptides was performed. As a result, the 43, 7 and 8 kDa components were found to commence with Ala-41, Ala-424 and Asp-466, respectively. These results suggest that after removal of the signal peptide, human arylsulfatase B undergoes proteolytic processing on at least two sites during maturation.
Kobayashi
T
T
Biochemistry Laboratory, Hokkaido University School of Medicine, Sapporo, Japan.
Honke
K
K
Jin
T
T
Gasa
S
S
Miyazaki
T
T
Makita
A
A
D000595:Amino Acid Sequence; D002803:Chondro-4-Sulfatase / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D005260:Female; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006801:Humans; D008969:Molecular Sequence Data; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy
D002803:Chondro-4-Sulfatase; D006026:Glycoside Hydrolases