The Importance Of Protein

With development of technology, scientist found that protein is an important composition of human body cells and tissues. In other words, Protein is the main part and participate in almost every process in intracellular organisms. The Protein is the most abundant biological macromolecule, which is the material basis of life, to be more precisely, is the essential organic building blocks of cells of living organisms and it provides the main bearer of life activities from bacteria to human beings. The protein is a substance that making by coiling and folding one or more certain spatial structure of polypeptide chains which are amino acids joined together by peptide bond that through the " dehydration condensation " approach to composition formed

Protein’s structure contain primary, that is amino acid sequence forming a polypeptide chains; secondary, that is the folding of a polypeptide chain, resulting in an alpha helix, beta-pleated sheet or a random coil structure; tertiary, that is completely folding of the sheets and helices of a secondary structure held in position by hydrophobic and hydrophilic interactions; quaternary, that is the assembly of multiple folded protein molecules in a multi-subunitcomplex. The protein folding is a physical process to form a functional three-dimensional structure. However, protein is usually random coil into specific functional structure, it is possible that misfolding happen and it will cause inactive protein that means not only loss its biological function but also give a toxic function(Fabrizio et al,2006). These essay will discuss the role of protein failure to fold and clump together that cause several neurodegenerative diseases, including CJD, Parkinson’s and Alzheimer’s

Yet diverse diseases affected in distinct regions of the brain, which result in divergent clinical manifestations. Neuronal loss is progressed cell death or apoptosis, there are at least three hypotheses to explain this phenomenon. The widely accepted hypothesis is the gain-of-toxic-activity that the protein misfolding and aggregation result in neurotoxicity. The direct evidence is misfolded proteins aggregation in vitro can cause neuronal apoptosis( Claudio, 2003). This theory of the amyloid beta-protein neurotoxicity have four kinds of interpretation. The first one, it is possible that extracellular aggregated protein may interact with specific receptors, which activation of a signaling pathway that can lead to apoptosis. The second one is intracellular aggregated protein cause recruitment of cellular factors and then damage the cells. The third one is the amyloid beta-protein and prion protein to form neurotoxicity due to formation of ion channels cause the membrane rupture and depolarization that result in changing the ionic homeostasis and the regulation of cell signaling, leading to cell death. The fourth one is the aggregation of the protein caused by oxidative stress, through the generating of free radicals, causing protein, lipid oxidation and increasing the intracellular calcium ion concentration and then the