In the next essay I will discuss and explain the relative function of prion protein. The prion protein, also known as PrPC, ''is a membrane-anchored protein with two N-glycosylation sites and, although it is highly expressed in neural tissues, its physiological functions have yet to be well established'' (Coordination Chemistry Reviews) . PrPC/PrP is found in the healthy brain in this form and is composed of 250 amino acids, but after simple misfolding in the secondary structure; this can alienate PrP and form PrPsc, which is the abnormal form of the prion protein. The infectious agent PrPsc causes neuropathological changes in the brain and immediately places the individual in the category of someone suffering from prion disease. PrPsc forms insoluble fibers and therefore cannot be studied well using nuclear mass resonance (NMR) and is also more resistant to protease digestion. Furthermore, ''Transmissible spongiform encephalopathies (TSEs) result from the conversion of membrane-bound prion protein from PrPC to PrPSc, the latter being the form of scrapie. Examples of TSEs include mad cow disease, chronic wasting disease in deer and elk, scrapie in goats and sheep, and kuru disease and Creutzfeldt-Jakob disease in humans'' (http:// www.ncbi.nlm.nih.gov/pmc /articles/PMC2904554/2014). The following diagram shows the conversion from PrPc to PrPsc: At present, the functional roles of prions remain an enigma, as the exact functional role is not known. Several attempts have been made to try to understand the physiological functions of the prion protein. One way to try to infer functions would be to see what other proteins interact with PrP, and some of the interactors would be key components of physiol... half of the article... (CNS) could also indicate another binding function of copper for PrP. In blood and blood plasma, amino acids are primarily what copper binds to, but the main component that it actively binds to is serum albumin, which readily absorbs copper 1 at its N terminus. CSF, however, contains more amino acids and lacks a high amount of serum albumin and other copper-binding constituents normally found in the blood. PrP is therefore hypothesized to play a similar role to albumin, helping to maintain copper homeostasis. Several studies have also shown that PrP opposes apoptosis reactions in some cells, protecting them from signals that would normally cause apoptosis. Mutagenesis experiments have shown that the PrP octarepeat domain is necessary to protect against the toxicity of the Doppel protein, which, if normally expressed, would lead to cell death.