Abstract
Sulfotransferase 1A1 (SULT1A1) (thermostable phenol sulfotransferase, TS PST1, P-PST) is important in the metabolism of thyroid hormones. SULT1A1 isolated from human platelets displays wide individual variations not only in the levels of activity, but also in thermal stability. The activity of the allelic variant or allozyme SULT1A1*1, which possesses an arginine at amino acid position 213 (Arg213) has been shown to be more thermostable than the activity of the SULT1A1*2 allozyme which possesses a histidine at this position (His213) when using p-nitrophenol as the substrate. We isolated a SULT1A1*1 cDNA from a human liver cDNA library and expressed both SULT1A1*1 and SULT1A1*2 in eukaryotic cells. The allozymes were assayed using iodothyronines as the substrates and their biochemical properties were compared. SULT1A1*1 activity was more thermostable and more sensitive to NaCl than was SULT1A1*2 activity when assayed with 3,5,3′-triiodothyronine (T3). Sensitivities to 2,6-dichloro-4-nitrophenol (DCNP) and apparent Km values for SULT1A1*1 and for SULT1A1*2 with iodothyronines were similar. Based on Km values, the preferences of these SULT1A1 allozymes for iodothyronine substrates were the same (3,3′-diiodothyronine (3,3′-T2)>3′, 5′,3-triiodothyronine (rT3)>T3>thyroxine (T4)>>3,5-diiodothyronine (3,5-T2). SULT1A1*1 activity was significantly higher than the SULT1A1*2 activity with T3 as the substrate. Potential differences in thyroid hormone sulfation between individuals with predominant SULT1A1*1 versus SULT1A1*2 allozymes are most likely due to differences in catalytic activity rather than substrate specifity.
| Original language | English |
|---|---|
| Pages (from-to) | 525-532 |
| Number of pages | 8 |
| Journal | Journal of Endocrinology |
| Volume | 171 |
| Issue number | 3 |
| DOIs | |
| State | Published - 2001 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Endocrinology
Cite this
Characterization of human liver thermostable phenol sulfotransferase (SULT1A1) allozymes with 3,3′,5-triiodothyronine as the substrate. / Li, X.; Clemens, D. L.; Cole, J. R.; Anderson, Robert J.
In: Journal of Endocrinology, Vol. 171, No. 3, 2001, p. 525-532.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterization of human liver thermostable phenol sulfotransferase (SULT1A1) allozymes with 3,3′,5-triiodothyronine as the substrate
AU - Li, X.
AU - Clemens, D. L.
AU - Cole, J. R.
AU - Anderson, Robert J.
PY - 2001
Y1 - 2001
N2 - Sulfotransferase 1A1 (SULT1A1) (thermostable phenol sulfotransferase, TS PST1, P-PST) is important in the metabolism of thyroid hormones. SULT1A1 isolated from human platelets displays wide individual variations not only in the levels of activity, but also in thermal stability. The activity of the allelic variant or allozyme SULT1A1*1, which possesses an arginine at amino acid position 213 (Arg213) has been shown to be more thermostable than the activity of the SULT1A1*2 allozyme which possesses a histidine at this position (His213) when using p-nitrophenol as the substrate. We isolated a SULT1A1*1 cDNA from a human liver cDNA library and expressed both SULT1A1*1 and SULT1A1*2 in eukaryotic cells. The allozymes were assayed using iodothyronines as the substrates and their biochemical properties were compared. SULT1A1*1 activity was more thermostable and more sensitive to NaCl than was SULT1A1*2 activity when assayed with 3,5,3′-triiodothyronine (T3). Sensitivities to 2,6-dichloro-4-nitrophenol (DCNP) and apparent Km values for SULT1A1*1 and for SULT1A1*2 with iodothyronines were similar. Based on Km values, the preferences of these SULT1A1 allozymes for iodothyronine substrates were the same (3,3′-diiodothyronine (3,3′-T2)>3′, 5′,3-triiodothyronine (rT3)>T3>thyroxine (T4)>>3,5-diiodothyronine (3,5-T2). SULT1A1*1 activity was significantly higher than the SULT1A1*2 activity with T3 as the substrate. Potential differences in thyroid hormone sulfation between individuals with predominant SULT1A1*1 versus SULT1A1*2 allozymes are most likely due to differences in catalytic activity rather than substrate specifity.
AB - Sulfotransferase 1A1 (SULT1A1) (thermostable phenol sulfotransferase, TS PST1, P-PST) is important in the metabolism of thyroid hormones. SULT1A1 isolated from human platelets displays wide individual variations not only in the levels of activity, but also in thermal stability. The activity of the allelic variant or allozyme SULT1A1*1, which possesses an arginine at amino acid position 213 (Arg213) has been shown to be more thermostable than the activity of the SULT1A1*2 allozyme which possesses a histidine at this position (His213) when using p-nitrophenol as the substrate. We isolated a SULT1A1*1 cDNA from a human liver cDNA library and expressed both SULT1A1*1 and SULT1A1*2 in eukaryotic cells. The allozymes were assayed using iodothyronines as the substrates and their biochemical properties were compared. SULT1A1*1 activity was more thermostable and more sensitive to NaCl than was SULT1A1*2 activity when assayed with 3,5,3′-triiodothyronine (T3). Sensitivities to 2,6-dichloro-4-nitrophenol (DCNP) and apparent Km values for SULT1A1*1 and for SULT1A1*2 with iodothyronines were similar. Based on Km values, the preferences of these SULT1A1 allozymes for iodothyronine substrates were the same (3,3′-diiodothyronine (3,3′-T2)>3′, 5′,3-triiodothyronine (rT3)>T3>thyroxine (T4)>>3,5-diiodothyronine (3,5-T2). SULT1A1*1 activity was significantly higher than the SULT1A1*2 activity with T3 as the substrate. Potential differences in thyroid hormone sulfation between individuals with predominant SULT1A1*1 versus SULT1A1*2 allozymes are most likely due to differences in catalytic activity rather than substrate specifity.
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U2 - 10.1677/joe.0.1710525
DO - 10.1677/joe.0.1710525
M3 - Article
VL - 171
SP - 525
EP - 532
JO - Journal of Endocrinology
JF - Journal of Endocrinology
SN - 0022-0795
IS - 3
ER -