The ubiquitin system, disease and drug discovery Research Paper

The ubiquitin system, disease and drug discovery - Research Paper Example According to (Hershko,1998,pg.425-79) â€Å"There are strong indications for roles of the ubiquitin system in development and apoptosis, although the target proteins involved in these cases have not been identified.†.Protein in ubiquting exists in chain format which is linear and consists of amino acids. The degradation of chain is possible and it is thermodynamically possible in an aqueous environment. When the degradation of protein happens this is known as protein – turnover. The balance which exists between the synthesis and its degradation determines the concentration level of protein in the cell. The studies conducted over protein turnover rates have revealed that some proteins are long lived while others are short lived. The cell majorly consists of long lived protein while short lived proteins which are regulatory protein are abnormal protein. Source – (Hersko,1998,pg 425-79) The Ub has a function to monitor the turnover of protein in the cell by regulati ng the degradation process. This regulatory function is largely important. By regulatory function of Ub the cells are able to eliminate protein that displays another function. Furthermore, such regulation observes that other process expressed by regulatory protein is shut down. There is another regulatory function displayed by the protein which is alternative in nature and it simply inactivates the protein. However, in case of this alternative regulation, these inactivated proteins can be mistakenly reactivated. Unfortunately, the Ub linked regulation is expensive energetically and if a regulation needs to be done once again then re-synthesize should be performed. The functioning of Ub is in a ATP – depended pattern. But what is the reason for this? The reason for this in order to target the protein machinery is required that can degrade the protein. The machinery is used just as a tag which marks the protein which needs to be degradation. The degradation is conducted by the 26Sproteasome. Speaking precisely, the proteins that are to be degraded are primarily tagged by conjugating them with ub and these tagged protein are them identified and shuttled to proteasome for the purpose of degradation. Dysfunction in much ubiquitin process has created pathological conditions where there was malignant transformation. Proliferation and cell growth are further controlled by ubiquitin mediated degradation of portooncogenes, tumor suppressors and components of signal transduction systems. The Ubiqutin – Proteasome Pathway If we mix ubiqutin, ATP and an abnormal protein we might think that the protein will conjugate with Ub. However, we would be wrong in this assumption. There is something else required to attach Ub to such a protein. The thing that is needs in many cases is the three kinds of enzymes. 1) Ub activating enzyme known as E1 enzyme. This enzyme is required in modifying Ub so that it can be in a reactive condition. 2) Ub conjugative enzyme known as E2 enzyme. This enzyme does the function of catalyzing the attachment of Ub to the substrate protein. 3) Ub ligases know as E3 enzymes. This enzyme function in align with E2 enzymes and this enzyme is important in identifying the substrate protein. Yeast contains many E1, E2 and E3 enzymes. For example. It has been found that yeast contains 13 various E2 enzymes. All these do the function of conjugation but also a specific