Fewer Exposed Lysine Residues May Explain Relative Resistance of Chicken Serum Albumin to In Vitro Protein Glycation in Comparison to Bovine Serum Albumin

Claire M. Anthony-Regnitz, Amanda E. Wilson, Karen L. Sweazea, Eldon J. Braun

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Protein glycation and formation of advanced glycation end products is associated with several diseases resulting from high blood glucose concentrations. Plasma albumin is directly exposed to circulating glucose concentrations and is therefore at greater risk of glycation than hemoglobin. As plasma glucose concentrations in birds are 1.5–2 times higher than mammals of similar mass, avian albumin may be particularly at risk of glycation. Thus, the goal of the present study was to compare the in vitro formation of glycated albumin in chicken serum albumin (CSA) and bovine serum albumin (BSA) exposed to a range of glucose concentrations over a 16-week period. The level of glycation for CSA and BSA was quantified using boronate affinity columns to separate glycated albumin from non-glycated albumin and calculating the difference in protein concentration of each sample. The results indicate that CSA is glycated to a lesser degree than BSA when the albumins are exposed to increasing concentrations of glucose (38.8–500 mM). This was most apparent at week sixteen (500 mM glucose) where BSA expressed a higher degree of glycation (37.8 ± 0.76%) compared to CSA (19.7 ± 1.06%, P < 0.05). Additionally, percent glycation at week sixteen was significantly higher than the glucose-free solutions for both BSA and CSA, indicating that glycation is glucose-dependent. Analyses of the protein structures suggest that the relative resistance of CSA to glycation may be due to fewer lysine residues and variations in protein folding that shield more lysine residues from the plasma. Moreover, comparisons of reconstructed ancestral albumin sequences show that the ancestor of birds had 6–8 fewer lysine residues compared to that of mammals.

Original languageEnglish (US)
Pages (from-to)653-661
Number of pages9
JournalJournal of Molecular Evolution
Volume88
Issue number8-9
DOIs
StatePublished - Nov 1 2020

Keywords

  • Advance glycation end products
  • Avian serum albumin
  • Birds
  • Plasma glucose

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics

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