Proteins, in addition to their many functions, also regulate the blood’s pH. The ideal blood pH ranges between 7.35 to 7.45. A small change in pH can have a major impact on the way our bodies work. In addition, protein denaturation prevents it from functioning properly. Albumin is a protein found in blood that is slightly acidic. It helps to maintain the balance between positive and negative charges.
Our blood contains phosphate and proteins to maintain the pH balance. The kidneys, which control acid-base balance, produce bicarbonate to help maintain the pH level within a normal range. Almost all proteins are buffers. Amino acids contain positively and negatively charged carboxyl groups that bind to hydroxyl and hydrogen ions. Proteins buffer almost two-thirds our blood.
A large portion of protein-containing foods contain amino acids. They are the backbone of our bodies. They participate in many bodily functions, and come in a variety of shapes and sizes. They are also structurally unique, and are designed to perform specific functions. There are two main types of proteins: fibrous and global. The latter has more important functions and is the most essential nutrient.
Zwitterions are amino acids that have the potential to ionize within their R-groups. This reactivity depends on the amino acid’s microenvironment. Table 2.1 summarizes the pKa values for amino acids. The pKa value can be used to predict the ionization/charge status of an amino acid. As the pH of the amino acid is altered, the pKa value will change accordingly.