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Electrospray Ionization Mass Spectrometry of Apolipoprotein CIII to Evaluate O-glycan Site Occupancy and Sialylation in Congenital Disorders of Glycosylation.
Wada, Yoshinao; Okamoto, Nobuhiko.
Affiliation
  • Wada Y; Department of Obstetric Medicine, Osaka Women's and Children's Hospital (OWCH), 840 Murodo-cho, Izumi, Osaka 594-1101, Japan.
  • Okamoto N; Department of Molecular Medicine, Osaka Women's and Children's Hospital (OWCH), 840 Murodo-cho, Izumi, Osaka 594-1101, Japan.
Mass Spectrom (Tokyo) ; 11(1): A0104, 2022.
Article in En | MEDLINE | ID: mdl-36060528
Congenital disorders of glycosylation (CDG) are inherited metabolic diseases that affect the synthesis of glycoconjugates. Defects in mucin-type O-glycosylation occur independently or in combination with N-glycosylation disorders, and the profiling of the O-glycans of apolipoprotein CIII (apoCIII) by mass spectrometry (MS) can be used to support a diagnosis. The biomarkers are site occupancy and sialylation levels, which are indicated by the content of non-glycosylated apoCIII0a isoform and by the ratio of monosialylated apoCIII1 to disialylated apoCIII2 isoforms, respectively. In this report, electrospray ionization (ESI) quadrupole MS of apoCIII was used to identify these biomarkers. Among the instrumental parameters, the declustering potential (DP) induced the fragmentation of the O-glycan moiety including the Thr-GalNAc linkage, resulting in an increase in apoCIII0a ions. This incurs the risk of creating a false positive for reduced site occupancy. The apoCIII1/apoCIII2 ratio was substantially unchanged despite some dissociation of sialic acids. Therefore, appropriate DP settings are especially important when transferrin, which requires a higher DP, for N-glycosylation disorders is analyzed simultaneously with apoCIII in a single ESI MS measurement. Finally, a reference range of diagnostic biomarkers and mass spectra of apoCIII obtained from patients with SLC35A1-, TRAPPC11-, and ATP6V0A2-CDG are presented.
Key words

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Mass Spectrom (Tokyo) Year: 2022 Document type: Article Affiliation country: Japan Country of publication: Japan

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Mass Spectrom (Tokyo) Year: 2022 Document type: Article Affiliation country: Japan Country of publication: Japan