title: Synthesis of a 125I-radiolabeled penicillin for penicillin-binding proteins studies.
abstract: Radioiodination of penicillin X (p-hydroxybenzylpenicillin) with 125INa, using the chloramine-T method, is simple and almost quantitative. The product thus obtained can be used without further purification for the penicillin-binding proteins (PBPs) assay. The chemical structure of 125I-penicillin X is very close to that of penicillin G, and the affinity of the two compounds for the PBPs are very similar. 125I-penicillin X can then advantageously replace [14C]penicillin G in these experiments, as its specific radioactivity is 2000 Ci/mol, in our preparations, instead of about 50 Ci/mol; thus, the experimental procedure is simplified and the autoradiography exposure time is reduced to 12-48 h.
mesh_terms: D001345:Autoradiography; D001426:Bacterial Proteins; D002250:Carbon Radioisotopes; D002352:Carrier Proteins / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D006602:Hexosyltransferases; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods*; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D011485:Protein Binding
chemical_list: D001426:Bacterial Proteins; D002250:Carbon Radioisotopes; D002352:Carrier Proteins; D007457:Iodine Radioisotopes; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G; C037825:penicillin X