Abstract
Chloramine-T iodination of protein A from Staphylococcus aureus and gel electrophoretic purification of the iodination mixture results in a stable tracer of high specific and functional activity. Following repeated gel electrophoresis of the tracer only a single component was observed. The specific activity of the 125I-protein A was between 30 and 55 muCi/micrograms. The binding of 125I-protein A to rabbit immunoglobulin exceeded 90% and the tracer competed effectively with unlabelled protein A in binding to cells incubated with sera containing surface antibodies. Storage of the tracer for up to 46 weeks resulted in a moderate decrease in maximal binding to immunoglobulin (from 91% to 64%), in TCA precipitable radioactivity (from 97% to 80%) and an approx. 30% decrease in the ability to detect cell bound immunoglobulin. It is concluded that gel electrophoretic purification of 125I-protein A produces a tracer with a very long shelf life.
| Original language | English |
|---|---|
| Journal | Journal of Immunological Methods |
| Volume | 71 |
| Issue number | 2 |
| Pages (from-to) | 193-201 |
| Number of pages | 9 |
| ISSN | 0022-1759 |
| Publication status | Published - 6 Jul 1984 |
Keywords
- Chloramines
- Electrophoresis, Polyacrylamide Gel
- Iodine Radioisotopes
- Isotope Labeling
- Staphylococcal Protein A
- Tosyl Compounds