Abstract
125I‐[Nle15]‐gastrin17 prepared by the iodogen method can be separated by reversed‐phase high performance liquid chromatography into two peaks, both of which elute after [Nle15]‐gastrin17. Direct determination of the specific activities of the two derivatives by microbore reversed‐phase HPLC indicated that they were the mono‐ and di‐iodinated species. In contrast the two peaks obtained with [Met15]‐gastrin17 iodinated under the same conditions eluted earlier, relative to the appropriate gastrin17 standard, than the [Nle15]‐gastrin derivatives. Treatment of either peak with 0.75 M dithiothreitol at 56°C or 95°C resulted in progressive conversion to compounds migrating in relative positions similar to the 125I‐[Nle15]‐gastrin17 derivatives. Direct determination of the specific activity of the earlier eluting [Met15]‐gastrin17 derivative before reduction indicated that it was the mono‐iodinated species. It thus appears likely that iodination of [Met15]‐gastrin17 by the iodogen method results predominantly in the formation of mono‐ and di‐125I‐[Met sulphoxide15]‐gastrin17. To avoid problems arising from oxidation of the methionine residue of gastrin during iodination, the use of 125I‐[Nle15]‐gastrin17 in binding studies is therefore recommended.
| Original language | English |
|---|---|
| Pages (from-to) | 159-163 |
| Number of pages | 5 |
| Journal | Biomedical Chromatography |
| Volume | 2 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1 Jan 1987 |
| Externally published | Yes |
Cite this
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Comparison of iodinated [Nle15]‐ and [Met15]‐gastrin17 prepared by reversed‐phase HPLC. / Seet, Lin; Fabri, Louis; Nice, Edouard C.; Baldwin, Graham S.
In: Biomedical Chromatography, Vol. 2, No. 4, 01.01.1987, p. 159-163.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Comparison of iodinated [Nle15]‐ and [Met15]‐gastrin17 prepared by reversed‐phase HPLC
AU - Seet, Lin
AU - Fabri, Louis
AU - Nice, Edouard C.
AU - Baldwin, Graham S.
PY - 1987/1/1
Y1 - 1987/1/1
N2 - 125I‐[Nle15]‐gastrin17 prepared by the iodogen method can be separated by reversed‐phase high performance liquid chromatography into two peaks, both of which elute after [Nle15]‐gastrin17. Direct determination of the specific activities of the two derivatives by microbore reversed‐phase HPLC indicated that they were the mono‐ and di‐iodinated species. In contrast the two peaks obtained with [Met15]‐gastrin17 iodinated under the same conditions eluted earlier, relative to the appropriate gastrin17 standard, than the [Nle15]‐gastrin derivatives. Treatment of either peak with 0.75 M dithiothreitol at 56°C or 95°C resulted in progressive conversion to compounds migrating in relative positions similar to the 125I‐[Nle15]‐gastrin17 derivatives. Direct determination of the specific activity of the earlier eluting [Met15]‐gastrin17 derivative before reduction indicated that it was the mono‐iodinated species. It thus appears likely that iodination of [Met15]‐gastrin17 by the iodogen method results predominantly in the formation of mono‐ and di‐125I‐[Met sulphoxide15]‐gastrin17. To avoid problems arising from oxidation of the methionine residue of gastrin during iodination, the use of 125I‐[Nle15]‐gastrin17 in binding studies is therefore recommended.
AB - 125I‐[Nle15]‐gastrin17 prepared by the iodogen method can be separated by reversed‐phase high performance liquid chromatography into two peaks, both of which elute after [Nle15]‐gastrin17. Direct determination of the specific activities of the two derivatives by microbore reversed‐phase HPLC indicated that they were the mono‐ and di‐iodinated species. In contrast the two peaks obtained with [Met15]‐gastrin17 iodinated under the same conditions eluted earlier, relative to the appropriate gastrin17 standard, than the [Nle15]‐gastrin derivatives. Treatment of either peak with 0.75 M dithiothreitol at 56°C or 95°C resulted in progressive conversion to compounds migrating in relative positions similar to the 125I‐[Nle15]‐gastrin17 derivatives. Direct determination of the specific activity of the earlier eluting [Met15]‐gastrin17 derivative before reduction indicated that it was the mono‐iodinated species. It thus appears likely that iodination of [Met15]‐gastrin17 by the iodogen method results predominantly in the formation of mono‐ and di‐125I‐[Met sulphoxide15]‐gastrin17. To avoid problems arising from oxidation of the methionine residue of gastrin during iodination, the use of 125I‐[Nle15]‐gastrin17 in binding studies is therefore recommended.
UR - http://www.scopus.com/inward/record.url?scp=0023526284&partnerID=8YFLogxK
U2 - 10.1002/bmc.1130020407
DO - 10.1002/bmc.1130020407
M3 - Article
VL - 2
SP - 159
EP - 163
JO - Biomedical Chromatography
JF - Biomedical Chromatography
SN - 0269-3879
IS - 4
ER -