Enzymes

• An enzyme is a biological catalyst that speeds up the rate of a reaction without taking part in the reaction itself.
• Enzymes allow reactions to occur much more rapidly, at a rate suitable to sustain life in both plants and animals.
• Metabolic reactions can be grouped into two main categories: Anabolic Reactions and Catabolic Reactions.
• Anabolic reactions involve building up large molecules from smaller ones, require energy, and are catalysed by an anabolic enzyme.
• Examples of anabolic reactions include photosynthesis, formation of muscle and DNA synthesis.
• Catabolic reactions involve breaking down large molecules into smaller ones, release energy, and are catalysed by a catabolic enzyme.
• Examples of catabolic reactions include respiration and digestion.
• All reactions that occur in the cell either produce or use energy, with the main sources of energy being Solar Energy and Cellular Energy.
• The main source of energy for all life is the sun, which is absorbed and converted to chemical energy in food (glucose) in the process of photosynthesis.
• Cellular Energy is the energy released by the reactions in a cell, which is used when animals eat plants.
• An enzyme is a protein made up of long chains of amino acids joined together by peptide bonds, and the chains of amino acids that form the enzyme are folded into a complex 3D shape.
• Pour the beads into the second funnel.
• The enzyme returns to its original shape and can work again.
• The substrate binds to the active site of the enzyme, forming an enzyme-substrate complex.
• Filter the hardened beads through filter paper in a funnel and rinse with water.
• The enzyme changes shape to fit better around the substrate, a process known as induced fit.
• Dissolve 1 g of sucrose in 100 ml of distilled water and pour 50 ml into each separating funnel.
• Repeat the test every 2 minutes until glucose appears in both beakers.
• Run off the remaining product from each funnel into the beakers and compare the turbidity of the solution from both funnels.
• Enzymes are specific - they act on only one particular substrate.
• The substrate is converted into the product.
• The product leaves the active site of the enzyme.
• Each enzyme has a certain area of its structure called the active site, which closely fits the shape of the specific substrate.
• Immediately test the products in the beakers with glucose strips - Clinistix.
• Leave the hardened beads to set for 10 minutes.
• Mix 2 g of yeast in 10 ml of distilled water and pour into one of the separating funnels.
• Enzymes are made in ribosomes.
• The substance that an enzyme acts on is called its substrate, and the substance(s) that the enzyme forms is called the product(s).
• Enzymes are specific, acting on only one particular substrate.
• Different enzymes work best within certain narrow pH ranges, and outside of this range the activity of the enzyme falls quite rapidly due to the enzyme losing its shape (becomes denatured).
• Most enzymes work best at around neutral pH, for example, Salivary amylase in the mouth and Pepsin which is released in the stomach work best at pH 2.
• The optimum/ideal pH is the pH the enzyme works best at.
• In general, enzyme activity increases with temperature up to 40 o C, above 40 o C enzymes rapidly denature (change shape) and do not work.
• The optimum temperature for human enzymes is 37 o C (body temperature), and the optimum temperature for plant enzymes is 20 o C - 30 o C.
• Shape changes and denaturation can no longer break down the substrate starch into maltose.
• It is easier to purify the product.
• Alcohol Fermentation takes place in some bacteria and fungi such as yeast.
• One of the biggest advances in bioprocessing was the invention of immobilised enzymes.
• To prepare an enzyme immobilisation, mix yeast with sodium alginate in a beaker using a glass rod, prepare a calcium chloride solution in another beaker, draw the yeast-alginate mixture into a syringe and from a height release it drop by drop into the calcium chloride solution, stir the beads using a glass rod, leave the beads to harden, filter the beads and wash with distilled water.
• In recent times bioprocessing has been used to produce a range of products including antibiotics, drugs, vaccines, biogas, food colourings, vitamins, enzymes and perfumes.