About 2000 protein spots of human Jurkat T-cells were detected by high resolution two-dimensional gel electrophoresis (2-DE) and were characterized in terms of their isoelectric point and molecular mass. A 2-DE database was constructed and is available at http://www.mpiib-berlin.mpg.de/2D-PAGE/. At present the database contains 67 identified protein spots. These proteins were identified after tryptic digestion by peptide mass fingerprinting with delayed extraction-matrix assisted laser desorption/ionization-mass spectrometry (DE-MALDI-MS). Proteins with a sequence coverage of at least 30% were introduced in the database. This sequence coverage could not always be obtained by using only the matrix alpha-cyano-4-hydroxycinnamic acid (CHCA) for the mass analysis. Therefore, an additional mass spectrum was recorded by using 2,5-dihydroxybenzoic acid (DHB). Usually, additional mass peaks were detected and together with the mass spectrum of CHCA this resulted in the desired sequence coverage.