Achemical that removes the amine groups from certain nucleotides would be classified as

Nucleotides are the building blocks of DNA, which comprises genetic material of an organism. Chemical or physical agents that cause changes in this genetic material are called mutagens. 

The chemical mentioned above would be classified as a chemical modifying mutagen, particularly a deaminator, which is a (nucleotide) base-modifying agent that removes amino groups from the nucleotides.