Enzymes 1 Flashcards
What are enzymes?
Biological catalysts that increases the rate of a chemical reaction of a chemical reaction without itself undergoing any permanent chemical change
- enzymes are specific
- they are located inside of cells, in the extracellular space or in the blood plasma
- they can be regulated
What are the functions of enzymes?
- Breakdown of nutrients
- Production of high energy molecule
- synthesis and assembly of cellular building blocks
What are substrates?
The reactants that are activated by the enzyme
What are apoenzymes?
Enzyme without its nonprotein component
What are holoenzymes?
An active enzyme with its nonprotein component
Differentiate Cofactors and Coenzymes?
Cofactors- a metallic nonprotein component e.g, Zinc (Zn2+)
Coenzymes- nonmetallic small organic molecule divided into co-substrates and prosthetic group
Define the category’s of Coenzymes
Co-substrates- transient association with the enzyme and dissociates into an altered form e.g. NAD+
Prosthetic groups- permanent association with an enzymes and the form is not changed at the end of the reaction
What is an active site?
Special pocket where substrate binds
What is the turnover number?
The number of substrate molecules converted to product per enzyme molecule per second
Describe the specifier of enzymes
Specificity:
- Enzymes are specific for a single molecule or a structurally related group of substrates
- Usually only 1 enzyme per reaction type
What are the c,asses of enzymes?
- Oxidoreductases
- Transferases
- Hydrolases
- Lyases
- Isomerases
- Ligases
What type of enzyme are oxidoreductases?
Catalyze oxidation-reduction reactions
What type of enzyme are transferases?
Catalyze transfer of C-, N- or P- containing groups
What kind of enzymes are hydrolases?
Catalyze cleavage of bonds by addition of water
What kind of enzyme are lyases?
Catalyze cleavage of C-C, C-S and certain C-N bonds
What kind of enzymes are isomerases?
Catalyze racemization of optical or geometric isomers
What kind of enzymes are Ligases?
Catalyze formation of bonds between carbon and O, S, N, coupled to hydrolysis of high-energy phosphates
What are 2 minor enzyme Groups?
Kinases
Phosphatase
What are the steps in an enzymatic reaction?
- Enzyme and substrate combine to form a complex E+S = ES complex
- The complex goes through a transition state- not quite substrate or product. ES=ES*
- A complex of enzyme and product is produced
- The product is released
EP= E+P
What are the 2 basic components of the active site ?
- catalytic site
- Binding site
What is the catalytic site of an enzyme?
Where the reaction occurs
What is the binding site of an enzyme?
Area that holds the substrate in proper place
Describe the shape of enzymes
Shape are complementary to the substrate and determines the specificity of the enzyme
Describe the interactions of enzymes
Enzymes use weak, non-covalent interactions to hold the substrate in place based on R groups of amino acids