Question

(This is BIOchemistry) For the appetite-related signaling molecule PYY3-36:

a.) What is the specific function of that molecule?

b.) What is the mechanism of that action (how does it do what it does)?

c.) How is that molecule made? Describe any prepro- and pro- forms and associated cleavages or covalent bonds or phosphorylations associated with the molecule.

d.) Describe how the molecule is regulated

(This problem relates to chapters 22, Biosynthesis of amino acids, nucleotides, and related molecules; and chapter 23, hormonal regulation and integration of mammalian metabolism, from the Lehninger Biochemistry textbook).

Answer 1

a) Peptide YY(3–36) [PYY(3–36)] is postulated to act as a hormonal signal from gut to brain to inhibit food intake. PYY(3–36) potently reduces food intake when administered systemically or into the brain. If action of endogenous PYY(3–36) is necessary for normal satiation to occur, then pharmacological blockade of its receptors should increase food intake.

b) peptide YY inhibited basal and stimulated cholinergic neurotransmission in the guinea pig stomach. In addition, peptide YY antagonized cyclic adenosine monophosphate-mediated release of acetylcholine through a pertussis toxin-sensitive mechanism.

c)