On the nature of rat hepatic and mouse olfactory sulfotransferases.
Rat hydroxysteroid sulfotransferase (HS-SULT) cDNAs, ST-40 and ST-20 are 90% identical in amino acid sequences and show different substrate specificities toward dehydroepiandrosterone (DHEA), androsterone (AD) and cortisol (CS). ST-40 enzyme is active toward the three substrates, whereas ST-20 enzyme is preferentially active for CS. First we prepared mutants of well conserved histidine, lysine and asparagine by site-directed mutagenesis. Secondly we constructed 20 chimeric HS-SULTs by reciprocal exchange of five protein domains between ST-20 and ST-40 enzymes. The studies on the expressed mutant and chimeric enzymes indicate the importance of the C-terminal region for the substrate specificity and the involvement of multiple regions for the enzyme activities. Next we determined the genetic loci of ST-40 and ST-20 by fluorescence in situ hybridization. Biotinylated ST-20 and ST-40 probes gave a pair of fluorescent spots on the same region of rat chromosome 1 and the loci of these genes were localized to the same chromosomal region of 1q21.3 --> q22.1. Finally we studied mouse olfactory phenol SULT (P-SULT). It was immunolocalized in the cytoplasm of mouse olfactory sustentacular cells and mouse nasal cytosols show high SULT activities toward phenolic aromatic odorants. We subsequently isolated a mouse P-SULT cDNA from mouse olfactory cDNA library. It encodes 304 amino acid polypeptide and is 94% identical with rat ST1C1 in amino acid sequences.
Matsui
M
M
Kyoritsu College of Pharmacy, Tokyo, Japan.
Tamura
H
H
Nagai
F
F
Homma
H
H
Miyawaki
A
A
Mikoshiba
K
K
D000595:Amino Acid Sequence; D000818:Animals; D015239:Arylsulfotransferase / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008969:Molecular Sequence Data; D009833:Olfactory Pathways / Q000201:enzymology*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015238:Sulfotransferases / Q000235:genetics*
D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D015238:Sulfotransferases; D015239:Arylsulfotransferase; C028152:alcohol sulfotransferase