Biochemistry Important Information Flashcards
What is an active site?
The area on an enzyme where a reaction occurs
What is activation energy?
The minimum amount of energy needed for a reaction to start
What is enzyme kinetics?
Measuring the rates of reaction of enzymes
What happens in reversible inhibition?
3
The inhibitor can bind to and dissociate from the enzyme
Activity is lost when the inhibitor is bound
Must wait for the enzyme to become free to overcome this inhibition
What happens in irreversible inhibition?
2
The enzyme is covalently modified and the activity is lost
Must replace the enzyme to overcome this inhibition
What happens in competitive inhibition?
2
The inhibitor binds at the active site
This prevents the substrate from binding
What are the three forms of reversible inhibition?
Competitive
Uncompetitive
Mixed
What happens in mixed inhibition?
The inhibitor can bind to the free enzyme of the enzyme substrate complex
How is Vmax and Km affected by competitive inhibition?
Binding to enzyme
Vmax is unchanged - i.e. it takes the same amount of enzyme to reach the max velocity
Km is increased - i.e. it takes more substrate to overcome the inhibitor
How is Vmax and Km affected by uncompetitive inhibition?
binding to ES
Vmax is reduced -reduced amount of product
Km is reduced - the more substrate added to more IES made
How is Vmax and Km affected by mixed inhibition?
Vmax is decreased
Hm is increased
How does pH affect enzyme activity?
3
Denaturation can occur at unsuitable pH levels
Changes in the charged state of amino acid components of enzymes
Substrates can become charged which may influence which enzymes can act on it
What is Beer Lambert’s Law?
Beer’s Law states that the concentration of a chemical solution is directly proportional to its absorption of light
Describe an alpha helix
4
Secondary structure of a protein
Hydrogen bonding
3D structure - helix - spring
The CO group of each amino acid forms a hydrogen bond with the NH group of amino acid four residues earlier in the sequence.
Describe a beta sheet.
5
Secondary structure of a protein
Hydrogen bonding
3D structure - sheets line up beside each other
The CO group of each amino acid forms a hydrogen bond with the NH group of amino acid
Either parallel = C -> N terminus matches up with another C -> N terminus chain or antiparallel = C -> N terminus matches up with N -> C chain
What two components of amino acids is a hydrogen bond formed between?
The CO group of one amino acid forms a hydrogen bond with the NH group of another amino acid
What are the consequences of resonance in the peptide bond?
3
The double bond is only a partial double bond - it resonates back and forth
It increases the polarity of the peptide bond
It restricts movement of the atoms in the bond (double bond is locked in position)
What is tertiary structure of a protein?
Side chain bonding e.g. disulphide bridges, hydrogen bonds, salt bridges, van der Waals, hydrophobic interactions
What are disulphide bonds?
Covalent link between the SH of two cysteine residues
What is a steriosomer?
A molecule that are mirror images of their structure
Define chirality
An object or a system is chiral if it is distinguishable from its mirror image; that is, it cannot be superimposed onto it.
Define conditionally non-essential amino acids.
Amino acids produced by the body but in lower amounts and outside supplementation may be required e.g. in case of pregnancy
Define essential amino acids.
2
Amino acids that cannot be produced by the body
They must be acquired via dietary or supplementary means
Define non-essential amino acids.
Amino acids that can be produced by the body and therefore not required via dietary or supplementary means
