Enzymes

Enzymes 26/10/2016Enzymes - Enzymes are Biological catalysts. They are found in all living cells which speed up chemical reactions in our cells/body. Without Enzymes, chemical reactions inside our cells/body will work far too slowly for life to exist. The Enzyme Activity is affected by both temperature and the pH level. Catalysts - Catalysts are chemicals that speed up the rate of a chemical reaction. The catalyst remain unchanged and are not used up in the reaction. The effect of catalase on Hydrogen PeroxideCatalase is an enzyme. It is found in most living cells. It breaks down hydrogen peroxide (H2O2) into water plus oxygen. catalaseAn equation for this is: Hydrogen peroxide -------------> Water + Oxygen (H2O2 Catalase H20 + O2) EnzymeThe Enzymes act on a substrate to produce a product. The general word equation for an enzyme controlled reaction is: substrate -------------> productEnzyme Specificity One Enzyme is specific to one substrate - One enzyme can only Catalyse one reaction, eg Catalase WILL ONLY break down hydrogen peroxide to water and oxygen. An enzyme and its substrate fit together like a lock and a key. The enzyme 'unlocks' the substrate to give a new product. Substrate - The Substrate is the substance upon which the enzyme acts resulting in the formation of an object. It joins to the active site. Product - The product is the molecule present at the end of the chemical reaction. Since an enzyme only acts on one specific substrate, each enzyme is said to be specific. Breakdown and buildup reactionsEnzymes are part of two types of reactions: Breakdown and buildup reactions. A breakdown reaction is a large substrate broken down into smaller product(s). A buildup reaction is a small substrate built up into a larger product. An example of a breakdown reaction is: Amylase, which is present in saliva that BREAKS DOWN starch into maltose (a sugar). The equation for this is: AmylaseStarch -------------> Maltose A buildup reaction may also be called as a Synthesis Reaction. An example of this is: Phosphorylase, which is present in plants that builds glucose-1-phosphate up into Starch. The equation for this is: glucose-1-phosphatePhosphorylase --------------------------------> Starch Enzyme Reactions:Breakdown reactions: AmylaseStarch --------------> Maltose CatalaseHydrogen peroxide -------------> water + oxygen LipaseFats ------------> Fatty acids + Glycerol Synthesis/Breakdown Reaction: PhosphorylaseGlucose-1-Phosphate ----------------------> StarchEnzymes and TemperatureEnzymes made of protein. All proteins are affected by temperature. Enzymes work slowly at low temperatures, but it does not do any damage to the enzyme. As the temperature increases the enzyme will work faster till a certain point. At high temperatures such as 50c, enzymes are destroyed and no longer work at all. The shape of the enzyme is permanently changed by the high temperature, so the substrate and enzyme don't fit together anymore. Effect of pH on EnzymespH is a measure of how acidic or alkaline a substance is. pH of less than 7 = Acidic pH of exactly 7 = Neutral pH of more than 7 = Alkaline Enzymes are also affected by the pH, just like the temperature. Enzymes will only work within a narrow range of the pH scale. The pH they work at depends on where they work in the body. For example, amylase works best at pH 7 - it is present in saliva, pepsin is an enzyme found in stomach acid - it works best at pH 2. Optimal ConditionsOptimal means 'best'. Optimum Conditions simple mean the conditions that enzymes work best at. Example of this is; Human enzymes work best at 37c - this is their optimal temperature. The optimal pH of different enzymes changes depending on where in the body it is active - e.g amylase (mouth) has an optimal pH of 7, whereas pepsin (Stomach) has an optimal pH of 2. Enzymes and BiotechnologyIn addition to being essential for life, enzymes are also used in a number of biotechnology industries. Examples include:-Using enzymes in biological washing powders. -Using enzymes in food modifications eg turning cloudy apple juice into clear apple juice.