A2- Proteins and Enzymes Flashcards
What region of amino acids are basic?
NH2
What region of amino acids is acidic?
COOH
What is a zwitterion?
a ion with separate positively and negatively charged groups (overall neutral charge)
When do amino acids form zwitterions?
isoelectric point (usually around pH 6)
What happens when amino acids are in alkaline conditions?
COOH dissociates, forming COO-
What happens when amino acids are in acidic conditions?
NH2 gains H+, forming NH3+
What is the primary structure of a protein?
sequence of amino acids
What is the secondary structure of a protein?
Hydrogen bonds cause B-pleated sheets or a-helix to form
When does a-helix form?
when NH2 groups are on the same side
What is the tertiary structure of a protein?
hydrogen, ionic and disulfide bonds make 3D shape
What is an enzyme?
protein-based biological catalyst, that speeds up rate of reaction by lowering Ea
Why are enzymes specific?
- a specific active site that must fit and have intermolecular forces with a specific substrate.
- This promotes the movement of electrons which lowers Ea
What is meant by the term ‘stereospecific’?
so specific that only one out of a pair of enantiomers will bind to the enzymes active site
How can enzymes be denatured?
changing temp and pH
Explain protein structure…
primary:
peptide bonds between amino acids, the specific sequence of amino acids
secondary:
H bonds between amino acids in same chain
alpha helix: Hydrogen bonds between peptide bonds every 4 amino acid residues, on the same chain
Beta pleated sheet: protein folds, hydrogen bonds between parallel peptide bonds
tertiary:
ionic between COO- and NH2 in R groups
disulfide; S-S
hydrogen, BETWEEN R GROUPS
VdWs: Between alkyl side groups
