Direct capillary electrophoretic detection of carbohydrate-deficient transferrin in neat serum

Transferrin, an iron transport protein found in serum and cerebrospinal flu id, is known to be microheterogeneous with respect to its carbohydrate and sialic acid content. The forms of transferrin deficient in sialic acid and/ or carbohydrate, termed carbohydrate-deficient transferrin (CDT), have been of clinical interest for almost two decades as a result of the initial fin ding that elevated CDT concentrations are associated with chronic, excessiv e alcohol abuse. We demonstrate the utility of capillary electrophoresis fo r examining the CDT sialoform profile via the direct electrophoresis of ser um. The need for negligible preelectrophoresis sample preparation and absen ce of postelectrophoresis processing dramatically decreases analysis time c ompared to slab gel-based separations. Using a fluorocarbon-coated capillar y containing a hydroxyethyl cellulose/ berate buffer, the high resolution s eparation of serum components is effected in less than 30 min. Under these conditions, the beta region proteins (including transferrin) are well resol ved from the alpha-2 and gamma zone proteins in a window where the individu al transferrin sialoforms can be detected. The usefulness of this method is demonstrated with the electrophoresis of serum from subjects known to be e ither nonalcoholic and alcoholic.