HbXL99 alpha: a hemoglobin derivative that is cross-linked between the alpha subunits is useful as a blood substitute.

Abstract

HbXL99a: A hemoglobin derivative that is cross-linked between the a subunits is useful as a blood substitute ( Communicated by Irving M. Klotz, June 11, 1987 (receivedfor review March 11, 1987 ABSTRACT Under deoxygenated conditions, bis(3,5-dibromosalicyl) fumarate reacts with hemoglobin selectively to cross-link the a subunits between Lys-a,99 and Lys-a299. We have characterized further the properties of this recently described hemoglobin and have demonstrated its utility as a blood substitute. The oxygen transport characteristics of the cross-linked derivative are very similar to those of whole blood. Under physiological conditions, the partial pressure of oxygen at half-saturation of hemoglobin is increased to 29 mm Hg (1 mm Hg = 133.3 kPa), compared to 12 mm Hg for hemoglobin A, fully compensating for the absence of 2,3-bisphosphoglycerate outside of the erythrocyte. The Hill coefficient is 2.9. The dependence of the oxygen affinity of HbXL99a on CO2 is also identical to that of hemoglobin A. The cross-link between the a subunits blocks dissociation of oxyhemoglobin into a4 dimers and thereby prevents renal excretion of the modified hemoglobin. In the rat, the half-life of HbXL99a in plasma, at a 15% volume exchange, is increased to 3.3 hr, compared to 90 min for hemoglobin A. Cross-linking HbXL99a intermolecularly with bis(sulfosuccinimidyl) suberate to form predominantly a mixture of dimers and trimers further increased the half-life of the hemoglobin within the circulation by about 2-fold. The rate of autooxidation of the transfused hemoglobin was found to be markedly reduced because of the presence of an endogenous reducing system in plasma.

Dissociation of local nitric oxide concentration and vasoconstriction in the presence of cell-free hemoglobin oxygen carriers

“…Experimental groups were as follows: (1) 0.9% NaCl (saline): saline infusion was the no-treatment group used to assess the effect of the experimental protocol; (2) ␣␣ cross-linked Hb (␣␣Hb): human Hb cross-linked between the ␣ chains with 3,5-bis(dibromosalicyl)fumarate under deoxy conditions and purified by ion exchange chromatography following previously described techniques. 25 This intramolecularly cross-linked conjugated Hb is a homogenous molecular species with an apparent molecular weight and volume comparable with unmodified Hb. It is the smallest molecular volume CFH in this study and is known to cause hypertension.…”

Enhancing Nitrite Reductase Activity of Modified Hemoglobin: Bis-tetramers and Their PEGylated Derivatives

“…αα-Fumaryl hemoglobin (DCLHb "Diaspirin cross-linked hemoglobin") was initially produced by Klotz and Walder (10). It was tested by the US Army and was advanced to clinical trials by Baxter Healthcare.…”

Cys-93-ββ-Succinimidophenyl Polyethylene Glycol 2000 Hemoglobin A

“…It is the first ␤ 93 ␤ 93 intramolecularly cross-bridged species reported to date. The previously described bisdibromosalicyl derivatives of aliphatic carboxylic acids and the bispyridoxal phosphates stabilize the tetrameric structure of HbA by cross-linking the amino groups within its central cavity (1,(5)(6)(7)(8)(9)(10). In contrast, included in the atomic model used to calculate the F calc structure factor magnitudes and phases.…”

“…In fact, some of the cross-linkers have been designed to mimic the interactions of the allosteric effectors. Their design strategy has focused on the complementarity between the stereochemistry of the tagging ends of the proposed bi-or tri-functional reagents and the reactive functional groups within the central cavity (1,(5)(6)(7)(8)(9)(10). In view of their location within the central cavity in the modified Hbs, these cross-links offer steric hindrance for interactions with the allosteric effectors compared with unmodified HbA.…”

“…Several intramolecular cross-bridging approaches have been developed over the years for the stabilization of Hb tetramer against dissociation into ␣␤ dimers (1,(5)(6)(7)(8)(9)(10). By and large, the currently available intramolecular cross-bridging reagents are targeted to the reactive functional groups within the central cavity of Hb in domains that interact with allosteric effectors.…”