Purity: > 95% by SDS - PAGE Format: Liquid. In 50 mM HEPES (pH7.5) 150mM NaCl, 1mM DTT, 10%glycerol. ubiquitin is a small protein that is composed of 76 amino acids and its sequence is highly conserved throughout evolution from invertebrates to mammals. In the cytoplasm, ubiquitin is involved in ATP-dependent nonlysomal proteolysis of various proteins. In the nucleus, ubiquitin is conjugated to histone2A and may play a role in regulation of chromatin structure and/or regulation of transcriptional activity. ubiquitin(76amino acid) was overexpressed in E.coli and purified by using conventional chromatography techniques.