Quadrupole-Time-of-Flight Mass Spectrometric Identification of Hemoglobin Subunits α, β, γ and δ in Unknown Peaks of High Performance Liquid Chromatography of Hemoglobin in β-Thalassemias

Abstract

This is the first report of quadrupole time-of-flight (Q-TOF) mass spectrometric identification of the hemoglobin (Hb) subunits, α, β, δ and γ peptides, derived from enzymatic-digestion of proteins in the early unknown peaks of the cation exchange chromatography of Hb. The objectives were to identify the unknown high performance liquid chromatography (HPLC) peaks in healthy subjects and in patients with β-thalassemia (β-thal). The results demonstrate the existence of pools of free globin chains in red blood cells (RBCs). The α-, β-, δ- and γ-globin peptides were identified in the unknown HPLC peaks. The quantification and role of the free globin pool in patients with β-thal requires further investigation. Identification of all types of Hb subunits in the retention time (RT) before 1 min. suggests that altered Hbs is the nature of these fast-eluting peaks. Relevancy of thalassemias to the protein-aggregation disorders will require review of the role of free globin in the pathology of the disease.

Keywords:

• High performance liquid chromatography (HPLC)
• mass spectrometry (MS)
• peaks
• quadrupole time-of-flight (Q-TOF)
• thalassemia

Acknowledgments

The authors’ sincere gratitude and thanks to Dr. Raudhawati Osman (Head of Unit) and Mrs. Norafzam Binti Muhamad at the Haematology Unit of the Pathology Department, HKL-KL, Kuala Lumpur, Malaysia, for their contribution to the data collection and sample processing and storage. We are grateful to all the respondents who participated in this study.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

This study was supported by the by University Sultan Zainal Abidin (UniSZA): [UniSZA/C/2/CRlM/431-2 (24)].