title: Effect of 2,3-diphosphoglycerate on O2-dissociation kinetics of hemoglobin and glycosylated hemoglobin using the stopped flow technique and an improved in vitro method for hemoglobin glycosylation.
abstract: Studies under equilibrium conditions have shown that the oxygen affinity of hemoglobin (Hb) is lowered by 2,3-diphosphoglycerate (2,3-DPG), the physiological allosteric effector in erythrocytes, and enhanced by glycosylation of Hb. The kinetics of oxygen release, as a function of 2,3-DPG and the degree of glycosylation have been determined using the stopped flow method and a new in vitro glycosylation procedure allowing adequate amounts of functionally intact hemoglobin to be obtained. The rate constant k of O2-dissociation in glycosylated Hb (8% HbA1c) was approximately 10% lower than in native Hb (4% HbA1c). The addition of 2,3-DPG in concentrations up to 20 mmol/l resulted in a progressive increase of k from 61.5 +/- 3.3 s-1 to 65.3 ae 4.1 s-1 for native Hb and from 56.8 +/- 5.2 s-1 to 59.4 +/- 4.1 s-1 for glycosylated Hb. We conclude that (a) the degree of glycosylation similar to that found in diabetic patients is responsible for a significant decrease of the oxygen dissociation velocity and (b) 2,3-DPG concentration similar to those occurring in vivo have only a weak effect on the oxygen dissociation velocity.
authors.affiliation: Department of Clinical Pharmacology, University Hospital, Frankfurt/Main.
authors.forename: J P
authors.initials: JP
authors.lastname: Marschner
authors.forename: T
authors.initials: T
authors.lastname: Seidlitz
authors.forename: N
authors.initials: N
authors.lastname: Rietbrock
mesh_terms: D019794:2,3-Diphosphoglycerate; D004163:Diphosphoglyceric Acids / Q000494:pharmacology*; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D010100:Oxygen / Q000378:metabolism; D010108:Oxyhemoglobins / Q000378:metabolism*
chemical_list: D019794:2,3-Diphosphoglycerate; D004163:Diphosphoglyceric Acids; D006442:Glycated Hemoglobin; D010100:Oxygen; D010108:Oxyhemoglobins