Online single-step analysis of blood proteins: the transferrin story.
The serum iron transport protein human transferrin (hTf) is a glycoprotein (MW approximately 79.6 kDa) containing two Asn-linked sites of glycosylation. The presence of specific glycoforms of hTf has been used as an indicator of carbohydrate-deficient glycoprotein syndrome (CDGS) or an indicator of alcohol abuse. The exact nature of the glycoforms described in the literature is controversial. In this work we demonstrate that the altered hTf glycoforms have lost one or both complete glycan side chains. Furthermore, we demonstrate using a combination of online immunoaffinity-postconcentration-mass spectrometry in conjunction with a blood spot cartridge that we can determine the relative quantities of the hTf glycoforms using <5 microL blood in under 30 min. This is in contrast to previous methods that used 1 mL and took 4 days. We show that this method can be useful to analyze hTf from CDGS and alcoholic patients.
Bergen
H R
HR
Biomedical Mass Spectrometry and Functional Proteomics Facility and Department of Biochemistry and Molecular Biology, Mayo Clinic/Foundation, Rochester, Minnesota 55905, USA.
Lacey
J M
JM
O'Brien
J F
JF
Naylor
S
S
D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D009439:Neuraminidase / Q000032:analysis; D021241:Spectrometry, Mass, Electrospray Ionization; D014168:Transferrin / Q000031:analogs & derivatives* / Q000032:analysis*
D006023:Glycoproteins; D014168:Transferrin; C056759:carbohydrate-deficient transferrin; D009439:Neuraminidase