Association of Radioactive Chromium with Various Components of Hemoglobin

1) When normal hemoglobin was labeled with Cr⁵¹ by incubation of wholeblood with Na₂Cr⁵¹O₄, or by incubation of hemolysates with either Na₂Cr⁵¹O₄or Cr⁵¹Cl₃, most of the Cr⁵¹ activity was associated with the electrophoreticallyrapid hemoglobin A₃. The formation of a Cr⁵¹ hemoglobin complex with anisoelectric point lower than that of hemoglobin was thought to be the mostlikely explanation of this finding.⁴

2) The radioactivity of Cr⁵¹-labeled hemolysates containing hemoglobin S,C, and A was found to be associated with the more rapid electrophoreticcomponents. This finding supports the hypothesis of a lower isoelectric pointof a Cr-hemoglobin complex.

3) The association of Cr⁵¹ activity with the polypeptide chains of hemoglobin was studied by two approaches: 1) determination of the labeling ofcomponents in hemolysates containing hemoglobin A (^A₂ ^A₂) and hemoglobin H (^A₄), and 2) determination of the labeling of polypeptide chainsof Cr⁵¹-labeled normal hemoglobin separated by the method of Huehns andco-workers.¹² Cr⁵¹ activity was found in both the naturally occurring chaincomponent (hemoglobin H) and in the chain component prepared by themethod of Huehns and co-workers.¹² These findings support the hypothesis ofothers^5,6 that chains of hemoglobin have a greater affinity for chromiumthan do chains.

Submitted on June 14, 1962 Accepted on August 14, 1962