Cyanogen bromide is an inorganic, toxic substance with the chemical formula CNBr. It is white and crystalline with a sharp odor. It is a tissue irritant and can be dissolved in water, alcohol, and ether. It melts at 52 degrees Celsius and boils at 61.4 degrees Celsius.
This chemical is used to extract gold from ores and other materials, in pesticides, and in the chemical synthesis of organic substances. It is also used in genetic engineering to cleave polypeptide chains (especially synthetic proteins) wherever the amino acid methionine occurs. It is also used to attach protein ligands to various supporting substances in preparation for affinity chromatography.
The information in this writeup was taken from the science dictionary at http://biotech.icmb.utexas.edu/; I oversaw the development of the dictionary (the website was mothballed in 1998) and I believe I wrote the entry this is based on.