Ubiquitin may be a little macromolecule that's found in the majority cellular tissues in humans and alternative eukaryotic organisms, that help to control the processes of alternative proteins within the body. Through a method called ubiquitination or ubiquitylation, An ubiquitin molecule will bind to a substrate macromolecule, dynamic the manner it functions. this could cause variety of various outcomes. It is most generally recognised for its role in caspase-mediated cell death of proteins, earning it the title of the molecular “kiss of death” for proteins, though it additionally plays a serious half in many alternative cellular processes associated with the regulation of proteins.