| Now
that the human genome has been deciphered,
much of the fanfare surrounding it has
transferred to the proteome, the full
complement of proteins made from the genetic
“blueprints” stored in our cells.
Proteins, after all, carry out most of the
work in the body, and an understanding of how
they behave, the press releases say, should
translate into a font of ideas for curing all
manner of ills. Yet living cells are more than
genes and proteins. Two other major classes of
molecules--carbohydrates (simple and complex
sugars) and lipids (fats)--play profound roles
in the body as well. These substances, too,
need to be considered if scientists are to
truly understand how the human machine
operates and how to correct its maladies.
Sugars in
particular perform an astonishing range of
jobs. Once regarded mainly as energy-yielding
molecules (glucose and glycogen) and as
structural elements, they are now known to
combine with proteins and fats on cell
surfaces and, so situated, to influence
cell-to-cell communication, the functioning of
the immune system, the ability of various
infectious agents to make us sick, and the
progression of cancer. They also help to
distinguish one cell from another and to
direct the trafficking of mobile cells
throughout the body, among other tasks. So
ubiquitous are these molecules that cells
appear to other cells and to the immune system
as sugarcoated....continued at Scientific
American Digital
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