DEPC: Molecular formula: C6H10O5 Formula weight: 162.1 Density: 1.12 g/mL Molarity: 6.9 M Refractive Index: 1.398 at 20oC Diethyl Pyrocarbonate (DEPC) is sensitive to moisture and to pH; it decomposes to ethanol and carbon dioxide in aqueous solution. It decomposes at 155°C. DEPC is also sensitive to ammonia, which causes decomposition to urethane, a possible carcinogen. DEPC is effective as a nuclease inhibitor. (It reacts with many enzymes containing -NH, -SH or - OH groups in their active sites. Typically, a 0.1% solution is used to inactive RNase (one milliliter of DEPC is added to 1 liter of water). The DEPC will not immediately dissolve, as evidenced by the appearance of globules. The mixture should be stirred until the globules disappear. The DEPC hydrolyzes over time to form ethanol and carbon dioxide. At this time the solution may be autoclaved to destroy the DEPC. DEPC has been used as a gentle esterifying agent and preservative. DEPC acts as a condensing agent between lysine e-amine groups and the carboxyl groups of aspartic or glutamic acid. It modifies purine residues in RNA by carboxyethylation of histidyl residues. It is considered sufficient to autoclave 0.1% DEPC solutions for 15 minutes per liter. A method to assay for DEPC uses 5-thio-2- nitrobenzoate. For general information and background, see references