Glutathionylated γG and γA subunits of hemoglobin F: a novel post-translational modification found in extremely premature infants by LC-MS and nanoLC-MS/MS

J Mass Spectrom. 2014 Feb;49(2):178-83. doi: 10.1002/jms.3326.

Abstract

Oxidative stress plays an important role in the development of various disease processes and is a putative mechanism in the development of bronchopulmonary dysplasia, the most common complication of extreme preterm birth. Glutathione, a major endogenous antioxidant and redox buffer, also mediates cellular functions through protein thiolation. We sought to determine if post-translational thiol modification of hemoglobin F occurs in neonates by examining erythrocyte samples obtained during the first month of life from premature infants, born at 23 0/7 - 28 6/7 weeks gestational age, who were enrolled at our center in the Prematurity and Respiratory Outcomes Program (PROP). Using liquid chromatography-mass spectrometry (LC-MS), we report the novel finding of in vivo and in vitro glutathionylation of γG and γA subunits of Hgb F. Through tandem mass spectrometry (nanoLC-MS/MS), we confirmed the adduction site as the Cys-γ94 residue and through high-resolution mass spectrometry determined that the modification occurs in both γ subunits. We also identified glutathionylation of the β subunit of Hgb A in our patient samples; we did not find modified α subunits of Hgb A or F. In conclusion, we are the first to report that glutathionylation of γG and γA of Hgb F occurs in premature infants. Additional studies of this post-translational modification are needed to determine its physiologic impact on Hgb F function and if sG-Hgb is a biomarker for clinical morbidities associated with oxidative stress in premature infants.

Keywords: LC-MS; glutathionylation; hemoglobin A; hemoglobin F; high-resolution tandem MS; nanoLC-MS/MS; oxidative stress; prematurity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Chromatography, Liquid / methods*
  • Fetal Hemoglobin / analysis*
  • Fetal Hemoglobin / chemistry*
  • Glutathione / chemistry*
  • Humans
  • Infant, Extremely Premature / blood*
  • Infant, Newborn
  • Molecular Sequence Data
  • Spectrometry, Mass, Electrospray Ionization
  • Tandem Mass Spectrometry / methods*

Substances

  • Fetal Hemoglobin
  • Glutathione