Q. 16.16 - An Introduction to General, Organic, and Biological Chemistry

Question

Explain why each of the following pairs are complementary proteins:

a. beans and outs

b. almonds and peanuts

Step-by-Step Solution

Answer

(a) Beans and oats are complementary protein sources. Oats lack the essential amino acid Iysine, which beans provide. Oats provide the essential amino acids methionine and cysteine that beans lack. That is why beans and oats form a complementary protein source.
(b) Almonds and peanuts are both good sources of protein. Almonds lack the essential amino acid lysine, which peanuts provide. Almonds provide the essential amino acids methionine and cysteine that peanuts lack. That is why almonds and peanuts form a complementary protein source.

Step 1: Introduction

Amino acids contain an amine$\left(-{\mathrm{NH}}_2\right)$  and carboxylic acid $(-\mathrm{COOH})$functional group. Both the functional groups are covalently bonded to the a-carbon. All proteins are constructed from amino acids. A dipeptide is formed when two amino acids undergo a reaction that results in the formation of an amide bond between the amine group of one amino acid and the carboxylic group of the other amino acid, which joins the two amino acids. Proteins are macromolecules composed of repeating subunits known as amino acids, which determine protein shape and function.

Step 3: Introduction

Only a portion of the essential amino acids are present in incomplete protein sources. To make complementary proteins, we combine two foods with incomplete proteins. All of the essential amino acids required by the body are found in complementary protein sources.

Step 3: Beans and oats

(a) Beans and oats are complementary protein sources. Oats lack the essential amino acid iysine, which beans provide. Oats provide the essential amino acids methionine and cysteine that beans lack. That is why beans and oats form a complementary protein source.

Step 4: Almonds and peanuts.

(b) Almonds and peanuts are both good sources of protein. Almonds lack the essential amino acid lysine, which peanuts provide. Almonds provide the essential amino acids methionine and cysteine that peanuts lack. That is why almonds and peanuts form a complementary protein source.