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What are the optimum operating conditions for enzymes? - Coggle Diagram
What are the optimum operating conditions for enzymes?
Factors that affect enzyme activity
Temperature - The enzyme rate of reaction increases rapidly as temperature increases. The enzyme and substrate move quicker, resulting in more collisions at the active site. There is an optimum temperature and once it reaches its maximum , any temperature higher than the optimum can negatively alter the structure of the active site. This leads to denaturation.
Substrate concentration- The higher the concentration, the more collisions between the enzyme and substrate at the active site. The optimum concentration is when it is high enough to ensure all active sites are be occupied.
pH- The optimum activity is when the pH is at its maximum. It is important to note that the optimum pH is different for all enzymes. A not optimum pH would denature enzymes, enzyme activity would decrease to 0, alters enzyme shape and substrates are unable to bind to active site.
Most optimum pH lies from pH 5 to 9, except for pepsin and arginase. The relationship between the rate of an enzymatic reaction and pH takes form of a bell-shape.
Inhibitors- It is something that slows down the activity of an enzyme. Competitive inhibitors is temporary and leaves the enzyme eventually. The inhibition levels depend on the substrate concentration as both the inhibitor and substrate compete for a place in the active site. Non-competitive inhibitors are irreversible and denature enzymes. These inhibitors are mainly used to allow a product to be produced in specific amounts and is also used in controlling reactions.
Antibiotics can kill certain bacteria needed for some enzymes to work their best. Hence, antibiotics may cause digestion issues such as diarrhoea as it affects digestive enzymes.
Statins (medications that lower cholesterol) can raise liver enzymes and muscle enzymes. They may increase the risk of damage to the liver or muscles.
Enzyme concentration - It affects the reaction rate as there is a lot of substrate to bind with the enzymes. Substrate and enzyme concentration go hand-in-hand as if the substrates concentration is a limiting factor, more enzymes would not matter as there's nothing to bind to. The higher the concentration, the closer it is to the optimum level and the quicker the rate of reaction.
Selected condition (pH) for oxidase
How it is calculated:
For oxidoreductase enzymes, the optimum pHs of the enzymes can be calculated using the rule based on proton transfer.
Optimum pH:
pH 6.5 - experiment conducted with temperature of 5 degrees
Stable pH levels:
pH levels 5-11 had a stable enzyme activity. pH levels lower or higher than the range decreased enzyme activity significantly.
How to measure enzyme activtity
Researching symptoms for specific enzymes and observing a person's function.
Eg; A person's digestive enzyme activity can be determined by observing ho well they digest food. If the person suffers from bloating, diarrhoea or gas, it can be assumed their enzymes are not working properly.
Medical procedures
Fecal elastase test - used to check stool for elastase enzyme that helps digest proteins
A pancreas blood test measures the levels of certain digestive enzymes your pancreas produces. These tests can check for how much of these enzymes are in your bloodstream.
Enzyme marker - a blood test to measure specific enzyme levels and identifies the risk of diseases caused by the lack of enzyme activity.
Instruments
A spectrophotometer measures enzyme activity by measuring the rate at which absorbance changes. The substrate or the product of the reaction will absorb light of the selected wavelength. If the product absorbs light, absorbance will increase as the enzyme acts. This mean a high enzyme activity.
Radiolabelling
Lab Procedure
Fluorescence - The fluorescent dye is released from the substrate by an enzyme-catalysed reaction and the higher the fluorescence, the more the substrate degrades compared to lower fluorescence.
Selected Enzyme (oxidase)
Function in eukaryotes:
Oxidase plays a role in cell respiration and aerobic energy production by using oxygen to oxidise its substrates.
Where is it found in eukaryotes? Oxidase is found in the mitochondria of eukaryotes.
Classification/group: Oxireductase class
Enzyme assay for oxyreductase group:
These enzymes have been assayed by estimating the acid formed, by pH titration or by measuring CO2 release .However, a large number of radiometric assays can also be used.
Group of Enzymes
Oxidoreductases catalyses the transfer of electrons from the elctron donor(molecule) to another electron acceptor(molecule).
Hydroxylase
Oxygenase
Peroxidase
Oxidase
Catalase
Hydrolases catalyses bond cleavages by reaction with water. Hydrolases breaks down nutrients into smaller units for digestion.
Lipase
Cellulase
glycosidases(amylase)
peptidases
Protease
Ligases catalyses the reaction of joining two large molecules by establishing a new chemical bond. Eg; linking two fragments of DNA
synthase
Threonyl-tRNA synthetase
Succinyl-CoA synthetase.
Carboxylase
Acetyl-CoA carboxylase
Lyases is found in the mitochondria catalyses the breakdown of chemical bonds through methods other than hydroxylosis
phenylalanine ammonia-lyase
citrate lyase
isocitrate lyase
hydroxynitrile
pectate lyase
Isomerase rearranges atoms which changes their bond within an atom
triose phosphate isomerase
bisphosphoglycerate mutase
photoisomerase
Transferases are located in the cytosol of the cells and catalyses the transfer of a group of atoms.
Acyltransferase.
Peptidyl transferase.
Methyltransferase.
Glycosyltransferase.