Peptide Hormones Flashcards
How are peptide hormones transported throughout the body
through the circulatory system without the need for carriers
Why are peptide hormones synthesized as needed
they have very short biological half-lives and are broken down quickly
What are prohormones
large polypeptide chains which are modified and cleaved into hormones (sometimes multiple)
Why are peptides effective even after travelling through the blood
They can work at low concentrations
Peptide hormones are very large so what type of receptors do they typically bind
GPCRs and kinase-linked receptors
What causes a protein to take on a ring structure or for two chains to be held together
Disulfide bonds
In what form is insulin initially produced
preproinsulin
Explain the production of proinsulin
The leader sequence of preproinsulin is cleaved in the ER lumen resulting in proinsulin
Explain the production of insulin
Proteases cleave at 2 sites removing the C chain
The A and B chains remain connected by disulfide bonds
What determines which hormones will be produced from a prohormone
the expression of the enzymes which cleave prohormones