These effects have been demonstrated and to a lesser extent, exploited for a limited number of Aldosterone enzyme systems. Although the science of enzyme immobilization has developed as a consequence of its technical utility, one should recognize that the advantages of having enzymes attached to surfaces have been exploited by living cells for as long as life has existed. In fact, there is experimental evidence that the immobilized state might be the most common state for enzymes in their natural environment. The attachment of enzymes to the appropriate surface ensures that they stay at the site where their activity is required. This immobilization enhances the concentration at the proper location and it may also protect the enzyme from being destroyed. The term ����immobilized enzymes���� refers to ����enzymes physically confined or localized in a certain defined region of space with retention of their catalytic activities, and which can be used repeatedly and continuously����. Besides the application in industrial processes, the immobilization techniques are the basis for making a number of biotechnological products with applications in diagnostics, bioaffinity chromatography, and biosensors. The major N-acetylcysteine amide components of an immobilized ChOx enzyme system are the ChOx, the matrix, and the method of attachment. The ChOx enzymes can be attached to the support by interactions ranging from reversible physical adsorption or ionic linkages to stable covalent bond formation via peptide conjugation. The covalent reactions commonly employed give rise to binding through amide, ether, thio-ether, or carbamate bonds. As a consequence of enzyme immobilization, some properties such as catalytic activity or stability become significantly changed. The concept of stabilization has been an important driving force for immobilizing ChOx enzymes. High-serum cholesterol is directly related to various health diseases, like arteriosclerosis, heart disease, hypertension, cerebral thrombosis, and coronary artery disease etc. Hence, the progress of reliable and high sensitive technique for the active and fast detection of cholesterol is an interesting topic recently. It is also enviable to build up a reliable and sensitive cholesterol biosensor, which can allow a suitable and fast detection of cholesterol in blood samples. Various methods have been commenced for the recognition of cholesterol such as, biochemical investigation using radioactive labels, HPLC analysis, and electrochemical detection.