Biochemistry and Genetics pt 2

Question 1

What enzyme converts Norepi to Epi? What stimulates the enzyme?

Answer 1

Phenylethanolamine-N-methyltransferase (PNMT)

Stimulated by cortisol

Question 2

What is the pathway of glucose stimulating insulin release in the pancreatic beta cells?

Answer 2

Glucose enters beta cells via the Glut-2 transporter and undergoes glycolysis and TCA cycle generating ATP.

Increased ATP levels bind to a constitutively open ATP-sensitive K channel causing it to close. Loss of basal K efflux causes membrane depolarization.

Voltage-dependent calcium channels open causing increased intracellular calcium levels and subsequent insulin release.