Protein Hydrolysis—Protein Classification Based on Shape Flashcards
When a protein or smaller peptide in a solution of strong acid or strong base
is heated, the peptide bonds of the amino acid chain are __________ and free
amino acids are produced. The ___________ is the reverse of the formation
reaction for a peptide bond.
hydrolyzed/hydrolysis reaction
Often, for limited denaturation changes, it is possible to find conditions under which the effects of denaturation can be reversed; this _________________, in which the protein is “refolded,” is called renaturation.
restoration process
Loss of water solubility is a frequent physical consequence of protein denaturation. The precipitation out of biochemical solution of denatured protein is called _______________.
coagulation
In surgery, heat is often used to seal small blood vessels. This process is called _____________.
cauterization
A temperature above _____________ is extremely
dangerous, as the body’s enzymes begin to be inactivated at this level.
1068F (418C)
disrupts hydrogen bonds by making molecules
vibrate too violently; produces coagulation, as in
the frying of an egg
heat
causes violent vibrations of molecules that disrupt hydrogen bonds
Microwave radiation
operates very similarly to the action of heat (e.g.,
sunburning)
UV radiation
causes molecules in globular shapes to extend to longer lengths, which then entangle (e.g., beating
egg white into meringue)
violent whipping or shaking
affects R-group interactions
detergent
interferes with R-group interactions because these solvents also can form hydrogen bonds; quickly denatures proteins in bacteria, killing them (e.g., the disinfectant action of 70% ethanol)
organic solvents (e.g., ethanol, 2-propanol, acetone)
disrupts hydrogen bonds and salt bridges;
prolonged action leads to actual hydrolysis of
peptide bonds
strong acids and bases
metal ions combine with ㅡSH groups and form
poisonous salts
salts of heavy metals (e.g., salts of Hg2+, Ag+, Pb21+)
reduces disulfide linkages to produce 9SH groups
reducing agent
A ____________ is a protein whose molecules have an elongated shape with one dimension much longer than the others. They tend to have simple, regular, linear structures. There is a tendency for such proteins to aggregate together to form macromolecular structures.
fibrous protein
A ______________ is a protein whose molecules have peptide chains that are folded into spherical or globular shapes. Generally, these are water-soluble substances.
globular protein
A _______________ is a protein that is found associated with a membrane system of a cell. Thus, such proteins tend to be water-insoluble and they usually have fewer hydrophobic amino acids than globular proteins.
membrane protein
It is the major protein constituent of hair, feathers, wool, fingernails and toenails, claws, scales, horns, turtle shells, quills, and hooves.
a-keratin
Introduction of _____________ within the several levels of coiling structure determines the “hardness” of an a-keratin.
disulfide bridges
____________, the most abundant of all proteins in humans (30% of total body protein), is a major structural material in tendons, ligaments, blood vessels, and skin; it is also the organic component of bones and teeth.
Collagen
The globular protein ___________ transports oxygen from the lungs to tissue.
hemoglobin
The globular protein ___________ functions as an oxygen storage molecule in muscles. It consists of a single peptide chain and a heme unit, and hemoglobin has four peptide chains and four heme units. Thus only one O2 molecule can be carried by this molecule.
myoglobin
