APPLICATION OF ENZYMES IN MEDICINE AND SURGERY


INTRODUCTION
The application of enzymes in medicine and surgery has become a source of concern to medical expert around the world who sees this new field of study as vital to human growth and development. Enzymes have continued to play an important role in most industrial areas as well as in the fields of medicine and surgery where it has a wide area of usefulness. We should note that enzymes are tiny catalyst needed by the body to either speed up chemical reaction in the body and aid several treatments methods.
Enzyme application in medicine and surgery is a fundamental biological process that is vital for the survival of all species. Their specific function is to catalyze chemical reactions. Enzymes have found wide and diverse applications at which enzymes increase the rate of reactions which approach to equilibrium. Enzymes play critical role in the metabolic activities of all living organisms whether humans, animals, plants or microorganisms and are widely applied in microbialtechnology and their diagnosis processes. Abnormality of the enzyme metabolism system leads to a number of metabolic diseases. It is shown that many diseases associate with many components of the enzyme metabolism systems are now widely applied in clinical examinations as special markers for diseases. An interesting discovery suggesting that new roles of enzymes as a potential link that associates to prevent metabolic disorder.
WHAT ARE ENZYMES
Enzymes are biological molecules (proteins) that act as catalysts and help complex reactions occur everywhere in life. Let’s say you ate a piece of meat. Proteases would go to work and help break down the peptide bonds between the amino acids
Enzymes are produced by cellular anabolism, the naturally occurring biological process of making more complex molecules from simpler ones. Source organisms include bacteria, fungi, higher plants and animals (White and White, 1997). Enzymes may be extracted from a given source organism by a number of different methods (Nielsen et al., 1996). Most of the organisms that produce commercial enzymes are fungi. These organisms are molds Rhizopus oryzae, Aspergillus niger, Rhizomucor meihei, blights such as Endothia parasitica and yeasts such as Saccharomyces and Candida sp.
In cells and organisms most reactions are catalyzed by enzymes, which are regenerated during the course of a reaction. These biological catalysts are physiologically important because they speed up the rates of reactions that would otherwise be too slow to support life (Porcelli et al., 2010). Enzymes increase reaction rates, sometimes by as much as one million-fold, but more typically by about one thousand fold. Catalysts speed up the forward and reverse reactions proportionately so that, although the magnitude of the rate constants of the forward and reverse reactions is are increased, the ratio of the rate constants remains the same in the presence or absence of enzyme (Qijun et al., 2010). Since the equilibrium constant is equal to a ratio of rate constants, it is apparent that enzymes and other catalysts have no effect on the equilibrium constant of the reactions they catalyze.
There are 6 classes of enzymes as follows:
Oxidoreductases: These enzymes are involved in oxidations and reductions of their substrates e.g., alcohol dehydrogenase, lactate dehydrogenase, xanthine oxidase, glutathione reductase, glucose-6-phosphate dehydrogenase.
Transferases: These enzymes catalyze the transfer of a particular group from one substrate to another e.g., aspartate amino transferase (AST), alanine aminotransferase (ALT), hexokinase, phosphoglucomutase, hexose- 1-phosphate uridyltransferase, ornithine carbamoyl transferase etc.
Hydrolases: These enzymes bring about hydrolysis e.g., glucose- 6 -phosphatase, pepsin, trypsin, esterases, glycoside hydrolases etc.
Lyases: These are enzymes that facilitate the removal of small molecule from a large substrate e.g., fumarase, argino succinase, histidine decarboxylase.
Isomerases: These enzymes are involved in isomerization of substrate e.g., UDP-glucose, epimerase, retinal isomerase, racemases, triose phosphate isomerase.
Ligases: These enzymes are involved in joining together 2 substrates e.g., alanyl-t-RNA synthetase, glutamine synthetase, DNA ligases.
Enzymes increase reaction rates by decreasing the amount of energy required to form a complex of reactants that is competent to produce reaction products. This complex is known as the activated state or transition state complex for the reaction. Enzymes and other catalysts accelerate reactions by lowering the energy of the transition state. The free energy required to form an activated complex is much lower in the catalyzed reaction (Jiang et al., 2007). The amount of energy required to achieve the transition state is lowered; consequently, at any instant a greater proportion of the molecules in the population can achieve the transition state. The result is that the reaction rate is increased.
While it is clear that enzymes are responsible for the catalysis of almost all biochemical reactions, it is important to also recognize that rarely, if ever, do enzymatic reactions proceed in isolation. The most common scenario is that enzymes catalyze individual steps of multi-step metabolic pathways, as is the case with glycolysis, gluconeogenesis or the synthesis of fatty acids. As a consequence of these lock-step sequences of reactions, any given enzyme is dependent on the activity of preceding reaction steps for its substrate (Abir et al., 2005). In humans, substrate concentration is dependent on food supply and is not usually a physiologically important mechanism for the routine regulation of enzyme activity. Enzyme concentration, by contrast, is continually modulated in response to physiological needs. Three principal mechanisms are known to regulate the concentration of active enzyme in tissues: (1) Regulation of gene expression controls the quantity and rate of enzyme synthesis. (2) Proteolytic enzyme activity determines the rate of enzyme degradation. (3) Covalent modification of preexisting pools of inactive proenzymes produces active enzymes.
APPLICATION OF ENZYMES IN MEDICINE AND SURGERY
Development of medical applications for enzymes has been at least as extensive as those for industrial applications, reflecting the magnitude of the potential rewards: for example, pancreatic enzymes have been in use since the nineteenth century for the treatment of digestive disorders. The variety of enzymes and their potential therapeutic applications are considerable.
In a few cases enzymes have been used as drugs in the therapy of specific medical problems (Devlin, 1986). Streptokinase is an enzyme mixture prepared from streptococcus. It is usefull in clearing blood clots that occur in the lower extremities. Streptokinase activates the fibrinolytic proenzyme plasminogen that is normally present in plasma. The activated enzyme is plasmin is a serine protease like trypsin that attacks fibrin, cleaving it into several soluble components.
As enzymes are specific biological catalysts, they should make the most desirable therapeutic agents for the treatment of metabolic diseases. Unfortunately a number of factors severely reduces this potential utility:
a. They are too large to be distributed simply within the body’s cells. This is the major reason why enzymes have not yet been successful applied to the large number of human genetic diseases. A number of methods are being developed in order to overcome this by targeting enzymes; as examples, enzymes with covalently attached external b-galactose residues are targeted at hepatocytes and enzymes covalently coupled to target-specific monoclonal antibodies are being used to avoid non-specific side-reactions.
b. Being generally foreign proteins to the body, they are antigenic and can elicit an immune response which may cause severe and life-threatening allergic reactions, particularly .on continued use. It has proved possible to circumvent this problem, in some cases, by disguising the enzyme as an apparently non-proteinaceous molecule by covalent modification. Asparaginase, modified by covalent attachment of polyethylene glycol, has been shown to retain its anti-tumour effect whilst possessing no immunogenicity. Clearly the presence of toxins, pyrogens and other harmful materials within a therapeutic enzyme preparation is totally forbidden. Effectively, this encourages the use of animal enzymes, in spite of their high cost, relative to those of microbial origin.
c. Their effective lifetime within the circulation may be only a matter of minutes. This has proved easier than the immunological problem to combat, by disguise using covalent modification. Other methods have also been shown to be successful, particularly those involving entrapment of the enzyme within artificial liposomes, synthetic microspheres and red blood cell ghosts. However, although these methods are efficacious at extending the circulatory lifetime of the enzymes, they often cause increased immunological response and additionally may cause blood clots.
In contrast to the industrial use of enzymes, therapeutically useful enzymes are required in relatively tiny amounts but at a very high degree of purity and (generally) specificity. The favoured kinetic properties of these enzymes are low Km and high Vmax in order to be maximally efficient even at very low enzyme and substrate concentrations. Thus the sources of such enzymes are chosen with care to avoid any possibility of unwanted contamination by incompatible material and to enable ready purification. Therapeutic enzyme preparations are generally offered for sale as lyophilised pure preparations with only biocompatible buffering salts and mannitol diluent added. The costs of such enzymes may be quite high but still comparable to those of competing therapeutic agents or treatments.

CONCLUSION
Enzymes are natural proteins that stimulate and accelerate biological reactions in the body. Enzymes, many of which are made in the pancreas, break down food and help with the absorption of nutrients into the blood. Metabolic enzymes build new cells and repair damaged ones in the blood, tissues, and organs. Though the American Cancer Society says that there have been no well-designed studies showing that enzyme supplements are effective in treating cancer we need look no further than the benefit that comes from stimulating and accelerating so many biological reactions but their usefulness in the medical field is necessary and have thus continued to play key roles in saving the lives of people around the globe.

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