Capillary electrophoretic analyses of β-trace protein and other low molecular weight proteins in cerebrospinal fluid from patients with central nervous system diseases

Abstract

Ordinary capillary-zone electrophoresis (CZE), as well as CZE in a sodium dodecylsulfate-containing polymer solution (SDS-CZE) and capillary isoelectrofocusing (CIEF), was applied to the analysis of low molecular weight proteins in cerebrospinal fluid (CSF) from patients with various neuropsychiatric disorders. Under the CZE conditions employed, a peaks of β-trace protein (βTP), which is the most abundant low MW protein in CSF, was clearly detected on the electropherograms of all the samples examined, and the CSF βTP level could be tentatively determined using allylamine added at a constant concentration as the internal standard. The results revealed that βTP in CSF was non-specifically increased in organic diseases in the central nervous system (CNS), especially in ones giving severe physical damage to the brain tissues. On the other hand. SDS-CZE allowed us to determine simultaneously the CSF minor low MW proteins other than βTP, such as β 2-microglobulin, ψ-trace protein, myelin basic protein, etc., while the CIEF electropherograms suggested that βTP were separated into several fractions with the different PI values. These capillary electrophoresis systems seem to be powerful as aids in the biochemical examinations of βTP and other low molecular weight proteins in CSF from patients with CNS diseases.