Amino
Acids on Earth
by
Nate Fergus
1.
The properties of Histidine are:
-
Basic, either uncharged or positively
charged, hydrophilic
-
Polar R group
-
Functional group is imidazole
ring
-
Often found in active sites
of enzymes where imidazole can switch between charged and uncharged to
catalyze making and breaking of bonds
2.
A derivative of Histidine would be:
3.
An interesting biological or pharmaceutical role of this histidine derivative
is:
-
Histamine
is released from mast cells during allergic reactions. B lymphocytes
in an allergen-sensitive person stimulate the production of immunoglobulin
E (IgE) which binds to mast cells in tissues and basophils in the blood.
This binding activates the enzyme, calcium ATPase, which opens calcium
channels in cell membranes. Activated mast cells and basophils then
pump calcium into the cells, releasing histamine from storage granules.
4.
On a biosphere on a distant planet outside our solar system, a different
but related amino acid is found:
-
On planet Pedestrio, Histipine,
and therefore Histaprine, is found. The nitrogen atoms in the imidazole
ring are replaced with phosphorus atoms. The three-legged screaming
alpacas that live there do not have any allergies because the phosphorus
atoms make Histaprine too heavy to be released from the mast cells.
