9 Protein Folding Flashcards
what is the general process by which insulin is prepared?
proteolysis
what is the difference between preproinsuin, proinsulin, and insulin? and where is each found?
- prepro has a signal sequence, an A and B chain, and a C peptide. found inside the cell in a reduced form
- pro insulin is created by cleaving the signal sequence from preproinsulin. Found in the ER in an exidized state
- insulin is made by cleaving the C peptide from proinsulin
is preproinsulin oxidized or reduced?
-reduced
is proinsulin oxidized or reduced?
oxidized
is insulin oxidized or reduced?
oxidized
when oxidation occurs, and preproinsulin is turned into proinsulin, what does this allow to happen?
the formation of disulfide bonds between the A and B chains, allowing for much greater stability
the cytoplasm of the cell is usually an oxidizing or reducing environment?
reducing (this is why preproinsulin is reduced and disulfide bonds are not present (Sulfurs bound to hydrogen)
proteins fold to maxmize what>
-weak, noncovalent forces
bone skin and tendon are made up of what type of collagen?
Collagen type 1
reticulin fibers are made up of what type of collagen?
collagen type 3
what are the two standard repeat sequences found in collagen?
Gly-Pro-random
Gy-pro-hydroxyproline
other than proline, what else is hydroxylated in collagen?
lysine
what does improper hydroxylation of collagen cause and what causes this?
- scurvy (lack of hydroxylation)
- vitamin C deficiency
what end of collagen begins to fold first? the formation of what begins this process?
- c terminus (in most proteins it is the N, which is synthesized first)
- disulfide bonds, intra and inter chain
what causes the elongated helical structure found in collagen?
steric hinderance between prolinesq