THE OXYGEN-AFFINITY OF CYTOCHROME BO' IN ESCHERICHIA-COLI DETERMINED BY THE DEOXYGENATION OF OXYLEGHEMOGLOBIN AND OXYMYOGLOBIN - K-M VALUESFOR OXYGEN ARE IN THE SUBMICROMOLAR RANGE

Apparent oxygen affinities for Escherichia coli cells and membranes co ntaining a terminal oxidase,vith only one type of ligand-binding heme, cytochrome o', were measured with oxyleghemoglobin and oxymyoglobin a s sensitive oxygen reporters. Two K-m values (0.15 to 0.35 mu M and 0. 016 to 0.085 mu M) were detected, well below values determined for the purified oxidase by insensitive electrode methods.