chapter 21 - protein and enzymes Flashcards
what is the primary structure of a protein?
sequence of amino acids in a protein chain
what does the secondary structure of a protein contain?
alpha-helix
beta-sheet
hydrogen bonds connecting the backbone segments
what the tertiary structure of a protein?
regions of secondary structure + overall bending of the protein chain
what is the quaternary structure of a protein?
overall whole structure of protein, composed of more than one polypeptide chain
which is the only amino acid that can do a disulfide bond?
cystine
what is this an example of?
hydrophobic interactions
what is the difference between simple vs conjugated proteins?
simple: composed only of amino acids
conjugated: composed of amino acids and non-amino acids
what is the role of non-amino acids within conjugated proteins?
to have an ester functional group (since amino acids are not capable of having an ester)
what type of disulfide bond?
intrachain disulfide bond
what type of disulfide bond?
interchain disulfide bond
what is the only amino acid that can do a disulfide bond?
cystine
how many oxygen molecules can hemoglobin transport? why?
4
because it has 4 heme subunits which can transport 1 oxygen each
what vitamin does collagen need? if deficient, what does this cause?
vitamin C
scurvy
what structures are inhibited during denaturation? hydrolysis?
denaturation: 2-4 protein structures
hydrolysis: all protein structures
what is a zwitterion?
a salt that contains both a positive and negative charge
what is a residue?
an individual amino acid within a chain
what is specificity?
limit of enzyme activity to a specific substrate, or specific reaction
what is turnover number?
the maximum number of substrate molecules acted upon by one enzyme per unit time
what enzyme and what reactant cause the highest turnover number?
catalase - which breaks down hydrogen peroxide into water and oxygen
what is an oxidoreductase for?
oxidation-reduction reactions
what is a transferase for?
transfer of functional groups
what is a hydrolase for?
hydrolysis reaction (turning 1 reactant into 2 proucts)
what is a isomerase for?
isomerization of substrate
what is a lyase for?
group elimination to form double bond or addition to a double bond
what is a ligase for?
bond formation (two items turn into 1 item)
what is a cofactor? coenzyme?
cofactor: nonprotein part of enzyme that does not bind to enzyme but aids in function
coenzyme: binds loosely to active site of enzyme
what type of enzyme is being used in this reaction?
oxidoreductase
what type of enzyme is being used in this reaction?
transferase
what type of enzyme is being used in this reaction?
hydrolase (1 reactant turning into 2 products)
what type of enzyme is being used in this reaction?
isomerase
what type of enzyme is being used in this reaction?
lyase
what type of enzyme is being used in this reaction?
ligase (turning 2 reactants in 1 product)
induced-fit model vs lock-and-key?
induced: current model explaining how enzyme flexibly attaches to substrate
lock: old explanation of how active site was fixed per the substrate it binded to
In regards to enzyme acting as catalysts, what is the proximity effect?
bringing substances and catalytic sites together
In regards to enzyme acting as catalysts, what is the orientation effect?
hold substances at exact distance/orientation necessary
In regards to enzyme acting as catalysts, what is the catalytic effect?
provide acidic, basic, etc groups required for catalysis
In regards to enzyme acting as catalysts, what is the energy effect?
lower the energy barrier by inducing strain in bonds
what is feedback control?
regulation of enzymes activity by amount of product further into reaction pathway
what is allosteric control?
Regulator that binds to enzyme to either activate or deactivate enzyme’s active sites
what is the difference between an uncompetitive inhibitor vs a competitive inhibitor?
uncompetitive: does not compete with substrate for active site/ reaction occurs less efficiently
competitive: binds reversibly to an active site preventing substrate from entering active site
what is a Zymogen?
compound that becomes an active enzyme after undergoing a chemical change
must be activated by cleaving a portion of the molecule.
what is pepsinogen an example of? what does the active enzyme become?
Zymogen
pepsin
what is covalent modification?
phosphorylation - addition and removal of a phosphoryl group
what is genetic control?
regulation of enzyme activity by control of synthesis of enzymes
what is the difference between what makes a macromineral vs a micronutrient?
macro: more than 100 mg per day required
micro: minute amounts required for enzyme function
where are water soluble vitamins found?
inside cells
what is a chiral mismatch?
when wrong enantiomer of a substrate cannot bind to active sites of enzyme
