title: Binding of [14C]erythromycin to Escherichia coli ribosomes.
abstract: Erythromycin binding to Escherichia coli ribosomes required K(+) and Mg(2+). Under optimal conditions, the dissociation constant for erythromycin binding to E. coli ribosomes was found to be 1.0 x 10(-8) M and 1.4 x 10(-8) M at 24 C and 5 C, respectively. One molecule of [(14)C]erythromycin was bound to each 70S ribosome at equilibrium. Binding of erythromycin to ribosomes was rapid and reversible. The specific rate constants for the forward and reverse reactions were 1.7 x 10(7) liters per mol per min and 0.15 per min, respectively.
mesh_terms: D002250:Carbon Radioisotopes; D003956:Dialysis; D004917:Erythromycin / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism* / Q000648:ultrastructure; D005374:Filtration; D008274:Magnesium / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D012335:RNA, Ribosomal / Q000378:metabolism; D011869:Radioligand Assay; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002250:Carbon Radioisotopes; D012335:RNA, Ribosomal; D004917:Erythromycin; D008274:Magnesium; D011188:Potassium