Factors Affecting Enzyme Action

Factors affecting enzyme action:
An enzyme controlled reaction is measured by it’s time course. The time it takes for a certain event to happen. There are two common events usually measured, the formation of the products of the reaction, or the disappearance of the substrate in the reaction.
Temperature affects the rate of an enzyme controlled reaction as it increases the kinetic energy, which makes the molecules move around more and collide more rapidly. This means the enzyme and substrate come together more frequently to form enzyme substrate complexes, and therefore, the rate of reaction increases. Although, at around sixty degrees Celsius, the enzyme would denature, as they are biological catalysts, which means they work at human body temperature, after this they would cease to work, so only a limited temperature rise increases the rate in an enzyme controlled reaction.
pH affects the rate in an enzyme controlled reaction, each enzyme has an optimum pH, and the further away from that optimum pH the pH gets, the less effective the enzyme is, and the lower the rate of the enzyme controlled reaction. It can alter the charge on the amino acids around the active site, which means bonds (of opposite charges) could not be formed between enzyme and substrate, and the complex would not be formed, making not products (lower rate), and it could cause some similar bonds holding the tertiary structure together, which means the enzyme would change shape, and the active site could change, and no products would be formed.
The substrate concentration can also affect this. With lower amount of substrate there is less for the enzymes to collide with, so the rate is lower. As this increases there is more to collide with, until there is the same amount of enzymes and substrates. This is the optimum rate of reaction, any excess substrate added after this are unable to find an active site, as they would all be occupied at that time, and no more complexes, and therefore products, could be made.
1) Enzymes function less well at lower temperatures, because there is less kinetic energy, and the enzymes and substrates are colliding less, so less enzyme substrate complexes are being made in that period of time.
2) Enzymes are biological catalysts, so they work at human body temperatures, of around 37 degrees Celsius. When the temperature gets higher then this the enzyme will then denature. Meaning that less or no complexes will be formed, as they won’t keep their shape, as bonds will break, and if they don’t have their shape, the active site will change and enzymes won’t fit. Therefore, no products will be made.
3) A) Food is heated to a high temperature before being canned to allow the enzymes that produce the harmful micro organisms to denature, as they are biological catalysts, and work at human body temperature, so temperatures high then this would make them denature and not work, so they can’t produce the micro organisms. B) Onions are preserved in vinegar as vinegar is acidic, and if it is acidic, which means the pH is 6 or below. This means that it must be in vinegar as the pH is no-where near the optimum of the enzyme, and it will cause bonds in either the active site, or the tertiary structure to break, changing the structure, so the substrate won’t fit, making the enzyme inactive, so no micro organisms.