Purity of Glycera dibranchiata monomer hemoglobin components III and IV determined by isoelectric focusing.

1. The Glycera dibranchiata monomer hemoglobin components III and IV display behavior upon high voltage isoelectric focusing which is similar, but not identical to the behavior demonstrated by monomer hemoglobin component II (Constantinidis and Satterlee (1987). Biochemistry 26, 7779-7786). 2. Both components III and IV show multiple line behavior and formation of significant amounts of apoprotein when solutions of each holoprotein are focused on polyacrylamide gels. 3. The apoprotein of each component focuses as a single line, indicating that this is the most unambiguous estimate of purity for these proteins. 4. The purity of the component III and IV preparations can be estimated to be at least 95%.