Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2015 Oct 16;5(4):2758–2781. doi: 10.3390/biom5042758

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2015 by the authors; licensee MDPI, Basel, Switzerland.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).

PMC Copyright notice

Annotated MALDI-TOF MS spectra of permethylated N-glycans of myoblasts from healthy control 1 (A), GFPT1 patient 1 (B), and the DOK7 patient (C). In each of A, B and C, the top panel shows the full spectrum of glycans and the bottom panel amplifies the mass range where the majority of tri- and tetra-antennary glycans are found, the starting point and ending point of which have been indicated by red arrows. Profiles were obtained from the 50% acetonitrile fraction from a C18 Sep-Pak column. All ions are [M + Na]⁺. The number indicated in the spectra is the mass to charge ratio (m/z) of the corresponding glycan ion. Since the ion is monocharged, the value of m/z is equal to the molecular weight value of the glycan. Annotations are based on the molecular weight, N-glycan biosynthetic pathway, and MS/MS data. Glycans at m/z 2966, 3777, and 4587 are clearly annotated, which is due to the fact that their structures are unequivocal because each antenna is capped with a sialic acid and thus they are homogeneous bi-, tri-, and tetraantennary glycans. However, the glycan structure is not always as unequivocal as the glycan at m/z 2966 as biosynthetically non-fully sialylated glycan molecular ion species could be made up of mixtures of structural isoforms. Therefore, for those heterogeneous multiantennary structures with extended LacNAc repeats, the annotations are simplified throughout by using biantennary structures with the extensions and NeuAcs listed outside a bracket. GlcNAc, Man, Gal, Fuc, NeuAc.

Annotated MALDI-TOF MS spectra of permethylated N-glycans of myoblasts from healthy control 1 (A), GFPT1 patient 1 (B), and the DOK7 patient (C). In each of A, B and C, the top panel shows the full spectrum of glycans and the bottom panel amplifies the mass range where the majority of tri- and tetra-antennary glycans are found, the starting point and ending point of which have been indicated by red arrows. Profiles were obtained from the 50% acetonitrile fraction from a C18 Sep-Pak column. All ions are [M + Na]⁺. The number indicated in the spectra is the mass to charge ratio (m/z) of the corresponding glycan ion. Since the ion is monocharged, the value of m/z is equal to the molecular weight value of the glycan. Annotations are based on the molecular weight, N-glycan biosynthetic pathway, and MS/MS data. Glycans at m/z 2966, 3777, and 4587 are clearly annotated, which is due to the fact that their structures are unequivocal because each antenna is capped with a sialic acid and thus they are homogeneous bi-, tri-, and tetraantennary glycans. However, the glycan structure is not always as unequivocal as the glycan at m/z 2966 as biosynthetically non-fully sialylated glycan molecular ion species could be made up of mixtures of structural isoforms. Therefore, for those heterogeneous multiantennary structures with extended LacNAc repeats, the annotations are simplified throughout by using biantennary structures with the extensions and NeuAcs listed outside a bracket. GlcNAc, Man, Gal, Fuc, NeuAc.