Chemical Structures

The structure of AAs consists of a central carbon atom that is bound to an amino group (-NH2), an acid group (-COOH), and a side chain (R group) with the following basic structure:


The R group is what gives each AA its identity and determines its specific potential functions in the body. At the pH of body fluids, free AAs exist as dipolar ions (zwitterions) in the following basic form:

The basic zwitterion form has no net electrical charge because the polar charges cancel each other out. However, some AAs have charged R groups that give them a net positive or negative charge. With the exception of glycine (R group = H), AAs can exist as D or L stereoisomers. The human body only uses L-AAs for protein synthesis (PS). The AA names used in this chapter refer to the L forms unless otherwise indicated. Figure 15.1 provides three additional illustrations of the general structure of most AAs.

Lower Your Cholesterol In Just 33 Days

Lower Your Cholesterol In Just 33 Days

Discover secrets, myths, truths, lies and strategies for dealing effectively with cholesterol, now and forever! Uncover techniques, remedies and alternative for lowering your cholesterol quickly and significantly in just ONE MONTH! Find insights into the screenings, meanings and numbers involved in lowering cholesterol and the implications, consideration it has for your lifestyle and future!

Get My Free Ebook

Post a comment