-
Amino acid, if R group is not H, the Amino Acid can exist in two ___ forms
enantiomeric
-
Modified free amino acids:
small molecules that bind to cell receptors, generally chemical messengers
-
Post-translationally modified AAs:
proteins may contain AAs that are modified after they are incorporated into the protein.
-
Peptide: __. As the amino group and the
carboxyl group link, ___ is lost.
- a polymer of about 2-100 AAs linked by the peptide(amide) bond
- Water
-
A peptide is written with the __-terminal end to the left and the __-terminal end
to the right.
N,C
-
The peptide bond is ___ and ___ due to the resonance contribution.
rigid, planar
-
Leucine enkephalin
a natural analgesic found in the brain
-
Oxytocin
Induces labor and aids in forcing milk from the mammary glands.
-
Vassopressin
regulates blood pressure
-
protein functions
- catalysis
- structure
- movement
- defense
- regulation
- transport
- storage
- stress response
-
Simple protein contain __.
only amino acids
-
conjugated protein contain ___.
prosthetic group
-
protein without prosthetic group?
apoprotein
-
another name of conjugated protein?
holoprotein
-
primary
amino acid sequence
-
secondary
- 3-D arrangement of backbone atoms in space
- H-bond
- alpha
- beta
-
Tertiary
- 3-D arrangement of all the atoms in space
- domains
- disulfide bonds
- salt bridges
- hydrophobic interactions
-
Quaternary
- 3-D arrangement of subunit chains
- H-bond
- disulfide bonds
- salt bridges
-
proteins with similar amino acid sequences are __.
homologous
-
beta sheet, anti parallel
-
-
Supersecondary Structure:
Reverse turns in a protein chain allow helices and sheets to align side-by-side
-
Common AA found at turns are
- glycine: small size allows a turn
- proline: geometry favors a turn
-
The subunits are called
promoters
-
allosteric?
a change in structure on one chain causes changes in structure at another site
-
Denaturation due to
- Strong acid or base
- Organic solvents
- Detergents
- Reducing agents
- Salt concentrations
- Heavy metal ions
- Temperature changes
- Mechanical stress
-
Stages of Folding
- Hydrophobic collapse
- Molten globules
-
chaperones
stabilize proteins while folding, by providing a ‘safe’ environment for exposed hydrophobic regions
-
Fibrous proteins have a high concentration of __ or __.
a-helix or b-sheet
-
Globular Proteins
bind substrates within a hydrophobic cleft
-
Hemoglobin
- tetrameric protein (two a-chains and two beta chains)
- positive allosteric
|
|
