Ask the instructor to provide the stereochemistry whenever possible. Course instructors will draw structures many different ways. If you are confused about stereochemistry, refresh yourself on Fischer projections from organic chemistry. Biochemists focus on L-amino acids, as depicted in Figure 1 (wedge bonds), but D-amino acids are relevant for pharmaceutical applications. The R group, or side chain, is unique for each amino acid as a result, the a-carbon is a chiral center, except for glycine where R = hydrogen. Also, some amino acids have unique traits that add to their functionality Carbon SkeletonĪll of the amino acids are composed of an amine(-NH 2) and a carboxylicacid (-COOH) linked by a central a-carbon (Figure 2). To learn pH effects or the physicochemical properties of individual AAs, it’s best to try to understand the process and how changing the microenvironment will alter how an AA will behave. Also be keen on the nomenclature and conventions presented to you in class. Keep the table with you like the periodic table of elements in chemistry, you will refer to this AA table throughout the course. The three letters in parentheses are the 3-letter shorthand, and the letter in the red circle is the 1-letter shorthand: e.g., arginine, Arg, R. To read Figure 1, the AA in the top left is arginine. Note that selenocysteine (Sec, U) is not a common amino acid and can be skipped. A table of the common amino acids is provided in Figure 1. Use flash cards, whiteboards, or any other method of repetitive memorization. To learn the structures, names, and shorthand, the best method here is memorization. That is a daunting task for 20 amino acids. Most biochemistry courses will require you to know the following: the amino acid name, the structure, the pKa of ionizable hydrogens, and both the 3-letter and 1-letter shorthand. Always keep in mind, structure gives function. Errors in amino acid placement do occur and can lead to cell death in some instances. The AAs are strung together by ribosomes that read the instructions given to it by the mRNA. These proteins are made up of smaller building blocks called amino acids (AA). Proteins are complex biomolecules that perform critical roles in the cell. When genes are expressed, the DNA is transcribed into mRNA that is then translated into proteins. In biochemistry, DNA holds the genetic code for life.
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