Preparation of 125I-protein A usable for up to 10 months in immunoassays

TY - JOUR

T1 - Preparation of 125I-protein A usable for up to 10 months in immunoassays

AU - Dyrberg, T

AU - Billestrup, Nils

PY - 1984/7/6

Y1 - 1984/7/6

N2 - 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.

AB - 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.

KW - Chloramines

KW - Electrophoresis, Polyacrylamide Gel

KW - Iodine Radioisotopes

KW - Isotope Labeling

KW - Staphylococcal Protein A

KW - Tosyl Compounds

M3 - Journal article

C2 - 6736658

SN - 0022-1759

VL - 71

SP - 193

EP - 201

JO - Journal of Immunological Methods

JF - Journal of Immunological Methods

IS - 2

ER -