Heat shock proteins (HSP) play a role in protein translocation, and folding and assembly, also under standard conditions, and accelerate and facilitate folding by inhibiting aggregation and defective bindings. HSPs are distinguished in categories according to their molecular weight. Hsp60 recognizes collapsed substrate proteins, which would aggregate otherwise, and folds them actively under consumption of ATP. Hsp70 on the other hand helps to maintain the unfolded condition of target proteins. The chaperone hsp90 family proteins are ubiquitous in prokaryotes and eukaryotes and apparently prevent the final steps of the protein folding process. Heat Shock Proteins support the maintenance of three dimensional structures of proteins for instance by protecting them from denaturation due to heat. They can be found everywhere in the organism and are expressed extensively, for example, under stress condition caused by exposure to high heat, UV-rays or ethanol. Many heat shock proteins belong to the family of chaperons which play a role in protein translocation, and folding and assembly, also under standard conditions.