Peptidylglycine alpha amidating
And the proopiomelanocortin neurons in the brain make other collections of peptides. Why do many sympathetic neurons make neuropeptide Y along with norepinephrine?
These are some of the questions that lure us forward into our studies.
PHM uses ascorbic acid (vitamin C) to reduce the two copper atoms that are bound to its catalytic core and molecular oxygen is the final component of the reaction.
PAL also requires a metal ion for activity; PAL contains zinc.
To our surprise, the modification requires the sequential action of two enzymes, a monooxygenase and a lyase.
In particular, the transmembrane domain and cytosolic domain of PAM need not be present for the enzyme to function.
' Now we ask detailed questions about how those enzymes function and how they get into the secretory granules to do their jobs?
And we ask how the secretory granules are moved to the correct place in the cell to await secretion, and why do they wait so long before secreting their contents on command?
The role of these non-catalytic domains seems to be in getting PAM to the right place in the cell so that it can do its job.
In particular, the cytosolic domain is essential for targeting PAM to the secretory granules of pituitary endocrine cells and for guiding PAM protein that has reached the cell surface back into secretory granules following internalization.