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What is Metabolism?
- The sum of all chemical reaction within a living organism.
- Metabolism = anabolism (building up) and catabolism (breaking down)
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What do we need to know about microbial metabolism?
- Metabolism forms the basis of all forms of microbilogy
- Knowledge of metabolism from the basis of antibiotic therapy
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What is catabolism?
It is the breakdown of complex organic molecules into simpler molecules.
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What is an anabolic reaction?
Anabolism is the synthesis of complex organic molecules from simpler molecules.
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What is the role of ATP (adenosine triphosphate) in metabolism?
ATP stores the energy generated by catabolic reaction and makes it available for anabolic reactions.
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What are enzymes?
- They are biolofical catalysts that speed up chemical reactions and are not consumed in the reaction.
- They have a unique shape and only work on specific substrates.
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How much faster does an enzyme make a reaction work?
They will increase reaction time by 10^8 to 10^10 times.
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Why are enzymes needed?
They are needed in order to increase reactions to be able to sustain life.
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How do enzymes work?
They decrease the activation energy required to initiate a chemical reaction.
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How to enzymes and substrates interact?
Each enzyme has an active site where only a specific substrate can fit into.
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What is an enzymes turnover number?
Is the maximum number of substrate molecules an enzyme molecule can convert to product each second.
- Example: DNA polymerase (DNA synthesis) --> 250 per/sec
- Catalase (breakdown of H2O2) --> 20,000 per/sec
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What is a simple enzyme?
Made entirely of protein.
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What does a conjugated enzyme consist of?
- It consists of a Apoenzyme (the protein component) and a Cofactor (non-protein component) such as Mg or Ca ions.
- An organic molecule that is a cofactor is called a coenzyme.
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What is it called when you have a Apoenzyme and a cofactor together?
Holoenzyme
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What is a apoenzyme.
It is a enzyme that requires a cofactor to become active.
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What coenzyme is important in cellular metabolism?
- NAD+ (Nicotinamid adenine dinucleotide) involved in catabolic reactions
- and NADP+ (Nicotinamide adenine dinucleotide phosphate)involved in anabolic reactions
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Name two other important coenzymes?
- Flavin: FMN and FAD flavin adenine dinucleotide
- Coenzyme A: Used in intermediate step between glycolsis and TCA
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What is Oxidoreductase
Oxidation-reduction (redox) reactions. Loss or gain of electrons
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What is Transferase
Used for the transfer of functional groups (e.g., -NH2 or -PO4
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What is Hydrolase
It cleaves bonds on molecules with the addition of water (Hydrolysis)
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What is Lyase
For the removal or addition of groups of atoms without hydrolysis
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What is Isomerase
Used for the rearrangement of atoms within a molecule
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What is Ligase
Used for joining two molecules (using energy from the breakdown of ATP)
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What factors can affect enzymatic activity?
Temperature, pH, Substrate concentration
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What is a Exoenzyme?
Are usually active only out side the cell, used to breakdown nutrients that are too large to enter the cell
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What is an endoenzyme?
Active inside the cell, and most metabolic enzymes are endoenzymes
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What is a metabolic pathway?
Is a pathway usually containing many steps each with an individual enzyme
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What are the different types of metabolic pathways.
- Linear -
- Cyclic - TCA
- Branched -
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How can you control a metabolic pathway?
By messing up the enzyme.
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What are the types of enzyme inhibitors?
Competitive and non-competitive
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What is a competitive inhibitor?
Fills the active site and competes with the substrate, are similar in shape to the substrate, but the enzyme does not have a reaction with the enzyme
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What is a noncompetitive inhibitor?
It interacts with a site other than the active site changing the shape of teh active site so that the substrate will not attach to the enzyme.
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What is feedback inhibition?
The end product of a metabolic pathway is a non-competitive inhibitor of the pathway.
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