Enrichment of low-copy-number gene products by hydrophobic interaction chromatography

Enrichment of proteins in solution is the goal of a purification process an d often a scientific challenge. We investigated the capacity of hydrophobic interaction chromatogaphy to enrich proteins, potential candidates for nov el drug targets. The soluble protein fraction of Haemophilus influenzae was fractionated over a TSK Phenyl column and the proteins resolved were analy zed by two-dimensional gel electrophoresis and matrix-assisted laser desorp tion ionization mass spectrometry. Approximately 150 proteins, bound to the column, were identified, 30 for the first time. Most of the proteins enric hed by hydrophobic interaction chromatography were represented by major spo ts, so that an enrichment of low-copy-number gene products was only partial ly achieved. The proteins enriched by this chromatographic approach belong to various protein classes, including enzymes, ribosomal proteins and prote ins with as yet unknown functions. The results include two-dimensional maps and a list of the proteins enriched by hydrophobic interaction chromatogra phy. (C) 1999 Elsevier Science B.V. All rights reserved.