Behavior of glycopolypeptides with empirical molecular weight estimation methods. 1. In sodium dodecyl sulfate

Abstract

The influence of the presence of oligosaccharide branches was examined with respect to the behavior of glycopolypeptides in empirical molecular weight estimation methods in the presence of sodium dodecyl sulfate (NaDodSO4). This examination was conducted by comparing the gel chromatographic and gel electrophoretic behaviors in the presence of NaDodSO4 of 13 glycopolypeptides of known chemical and physical properties to those of regular polypeptides. Errors in the gel chromatographic molecular weight for glycopolypeptides in NaDodSO4 varied from -22% to +10% and indicated that the hydrodynamic behavior of the glycopolypeptide--NaDodSO4 complex could not be correlated with the amount of carbohydrate in the glycopolypeptide. NaDodSO4 binding measurements on a number of the glycopolypeptides suggest that the polypeptide moiety binds the nominal weight ratio of NaDodSO4, while the carbohydrate portion exhibits little or no NaDodSO4 binding. As has been reported by others, the polyacrylamide gel electrophoretic behavior of glycopolypeptide--NaDodSO4 complexes yielded abnormally high molecular weight estimates. In general, the error of these estimates diminished with decreasing porosity of the gel; however, each glycopolypeptide behaved in a unique fashion. Treatment of the electrophoretic data by any of several empirical means provided no reliable way to correct for the glycopolypeptides' aberrant behavior.

A radioimmunoassay for the detection of molecular forms of human plasma kininogen

“…As shown in [23] no carbohydrate was detectable in the bovine Iil4, kininogen L-chain and there is only a slight difference in the carbohydrate content of the H-chains of bovine HM, and IN, kininogens [24]. Glycopeptides also routinely migrate slower than polypeptides of the same Mr-value when subjected to SDS-PAGE [25]. Further favourable evidence is the observation [26] that IJ!fr kininogen behaved as a 52 000 Mr protein in both non-dissociating and dissociating conditions.…”

Neurotoxic protein oligomers — what you see is not always what you get

“…Artifactual aggregation induced by SDS has been observed for Hepatitis B surface antigen polypeptides [26], bradykinin [27], b(2)-glycoprotein I [28], and collagen [29]. In addition to aggregation, conformational changes in the presence of SDS may cause aberrant electrophoretic mobility, a phenomenon that has been reported for various proteins [30,31], including Ab [32].…”

Auxin-Responsive Genes AIR12 Code for a New Family of Plasma Membrane b-Type Cytochromes Specific to Flowering Plants

“…(A-D), Purified recAIR12 eluted from the last gel filtration chromatography purification step (9 mg for A and B, 140 ng for C, and 9 mg for D); lane 2 (A-C), same as for lane 1, but after incubation for 1 h at 37°C with EndoH; in C, recAIR12 was 47 ng; lane 3 (A), EndoH (1 mg). Gels were stained by Coomassie Brilliant Blue (A) or glycoprotein staining (B; Leach et al, 1980). C, Western-blot analysis was performed using rabbit antisera against recAIR12 expressed in E. coli (see "Materials and Methods" for details).…”

“…Gels were stained with Coomassie Brilliant Blue R-250. The staining of glycoproteins was done according to Leach et al (1980).…”