Effect of some physical features and of amino acid substitutions on the mechanical precipitation of hemoglobin.

Abstract

In 1973 Asakura demonstrated that, following mechanical shaking, oxy-Hb S was much less stable than oxy-Hb A (Nature 244: 437, 1973). We have studied the mechanical stability of Hb Crétil (beta 89 Ser leads to Asn), Hb Hope (beta 136 Gly leads to Asp), Hb Strasbourg (beta 23 Val leads to Asp), and the hybrid Hb S/Stanleyville-II (beta 6 Glu leads to Val: alpha 78 Asn leads to Lys) by the method of Roth et al. (Blood 45:377, 1975). Hb Créteil, Hb Hope, and Hb S/St-II were sensitive to mechanical shaking, while Hb Strasbourg was more stable than Hb A, a hitherto undescribed finding. The precise mechanisms responsible for this precipitation are not known. From comparisons with published results, but excluding thermosensitive Hbs, we conclude that: - standard methods for isolation of hemoglobins modify its mechanical stability, - alpha mutation increases the mechanical stability of Hb S in the hybrid Hb S/St-II, - some mutations produce a more stable hemoglobin than Hb A.