Module 2 - Enzymes Flashcards
What is an enzyme?
An enzyme is a biological catalyst that can speed up metabolic reactions in living orgs
What can catalysts do?
Speed up chemical reactions
Catalyse conversions of large amount of substrates into products
What is an enzymes ‘turn over number’?
Number of reactions that an enzyme can catalyse per second
Why are enzymes so efficient?
They can work fast in low temperatures, neutral pH and at normal pressures
More specific than chemical catalysts
Don’t produce unwanted by products/ rarely make mistakes
How does an enzymes structure determine its function?
They may need help by cofactors
If there is a gene mutation then the amino acid sequence is altered altering the tertiary structure preventing it from functioning
Causes a metabolic disorder
What are intracellular enzymes?
They are enzyme working inside a cell usually in metabolic pathways
What are catabolic and anabolic pathways?
Catabolic - breaking down of molecules into smaller ones releasing energy
Anabolic - synthesise large molecules from smaller ones
What is amazing about the enzyme catalase?
Found in nearly all living orgs Prevents cells from being damaged by reactive oxygen by breaking down hydrogen peroxide (by product of metabolic reactions to water or oxygen) Fastest acting enzyme Contains haem group WBC use it to kill invading microbes
Describe the functions of some extra cellular enzymes
Amylase - produced in salivary gland and acts in the mouth to digest starch
Trypsin - made in pancreas and acts in the lumen of small intestine to digest smaller peptides
What is a prosthetic group?
A cofactor permanently bound by covalent bonds to an enzyme molecule
Eg
Enzyme carbonic anhydrase contains a zinc prosthetic group to its active site
What is the enzyme substrate complex?
Enzyme and substrate molecule temporarily bind to form this
Describe how two types of cofactors act
Some cofactors act as co-substrates by aiding the substrate to form the correct shape to bind to the active site
Some cofactors change the charge distribution on surface of enzyme active site or substrate to help make temporary bonds
What are co enzymes?
Small organic non-protein molecules that temporarily bind to active site of enzymes
What is the Lock and Key Hypothesis?
Active site has a complimentary shape to the substrate molecule like a key fitting into a lock
Either molecules are formed or broken
What is the ES and EP complex?
ES is the enzyme substrate complex
EP is the enzyme product complex
