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- Title
Sulfating-Activity and Stability of cDNA-Expressed Allozymes of Human Phenol Sulfotransferase, ST1A3*1 (213Arg) and ST1A3*2 (213His), Both of Which Exist in Japanese as Well as Caucasians1.
- Authors
Ozawa, Shogo; Shimizu, Makiko; Katoh, Takahiko; Miyajima, Atsuko; Ohno, Yasuo; Matsumoto, Yoshiaki; Fukuoka, Masamichi; Tang, Yong-Ming; Lang, Nicholas P.; Kadlubar, Fred F.
- Abstract
We recently found single amino acid substitutions (J13Arg/His and 223Met/Val) in polymorphic human phenol-sulfating phenol sulfotransferase (SULT: cDNAs encoding ST1A3, P PST or HAST1/2) among Caucasians and African-Americans. In a Japanese population (n =143), allele frequencies of 213Arg and 213His were 83.2 and 16.8% respectively, but the 223Val allele was not found. 213His homozygosity was reportedly associated with both very low (> 7-fold) sulfating activities of p-nitrophenol (at 4/tM) and low thermostability in platelets. Sulfating-activity determinations using recombinant 213Arg- and 213His-forms (ST1A3*1 and ST1A3*2, respectively) did not, however, reveal appreciable deficiency in [35S]3’-phosphoadenosine 5-phosphosulfate (PAPS)-dependent sulfation of p-nitrophenol (4 pM) by ST1A3*2 (7.5 vs. 10.2 nmol/min/nmol SULT for ST1A3). Kinetic parameters for p-nitrophenol for p-nitrophenol sulfation supported the slight decrease in sulfating activities at 4 /iM (Km, 0.82 vs. 1.75 /iM; Vmaxy 13.2 vs. 13.1 nmol/min/nmol SULT, respectively, for ST1A3*1 and *2). p-Nitrophenyl sulfate dependent 2-naphthol sulfation by ST1A3‘2 was 69% of that by ST1A3*1 (p<0.05). However, ST1A3*2 was remarkably unstable at 45 and 37*C as compared to ST1 A3*1. The lower p-nitrophenol sulfating activity of ST1A3*2 may explain the lower platelet p-nitrophenol sulfation in ST1A3*2 homo-zygotes. Protein instability and ST1A3 gene regulation may be both involved in the polymorphism of p-nitrophenol sulfation in human tissues.
- Subjects
AMINO acids; ISOENZYMES; ANTISENSE DNA; DNA; ANTISENSE nucleic acids
- Publication
Journal of Biochemistry, 1999, Vol 126, Issue 2, p271
- ISSN
0021-924X
- Publication type
Article
- DOI
10.1093/oxfordjournals.jbchem.a022445