Proteins Flashcards
How do you form zwitterion?
Remove H+ from COOH
Add H+ to NH2
What happens when you lower pH of zwitterion?
H+ added to COO-
Positive charge
What happens when you increase pH of zwitterion?
H+ removed from NH2
Negative charge
What time of hormone is insulin?
Peptide hormone
Where is insulin produced from?
Beta cells, pancreas
What does insulin do?
Regulate metabolism of carbohydrates, fats + proteins
By promoting absorption of glucose from blood to liver
Why is insulin injected
Too large to pass through phospholipid bilayer of GI tract
+ protein = digested by enzymes in GI tract
Why is folding important?
NOT CORRECT folding = might not fit receptor
Does correct folding require energy?
YES
What is protein in functional, folded conformations called?
Native proteins
What are folds held together by?
Sulphur, peptide + covalent bonds
London forces
Metal ions stabilise protein
What does Ca2+ do in calmodulin?
Make protein more stable = lowers energy state = low Gibb’s Free Energy state
Why do many proteins not have disulphide bonds?
Within cell = highly reducing as high conc reductants = sulphur used up in cell
Where are disulphide bonds normally found?
Secreted, extracellular proteins
What is an example of a protein with disulphide bonds?
Insulin
2x disulphide bonds
