CCDC23 (coiled-coil domain containing 23) is a 66 amino acid protein encoded by a gene mapping to human chromosome 1. Chromosome 1 is the largest human chromosome spanning about 260 million base pairs and making up 8% of the human genome. There are about 3,000 genes on chromosome 1, and considering the great number of genes there are also a large number of diseases associated with chromosome 1. Diseases associated with CCDC23 include endotheliitis. Recombinant human CCDC23 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.