Proteins Lecture 9

Proteins

• Proteins are complex organic compounds composed of a chain of amino acids.
• They provide energy for the body and are an important component of every cell.
• Hair and nails are mostly made of protein.
• Proteins are used to build and repair tissues, make enzymes, hormones, and other body chemicals.
• They are an important building block of bones, muscles, cartilage, skin, and blood.

Macronutrients and Micronutrients

• Protein is a macronutrient, meaning the body needs relatively large amounts of it.
• Unlike fat and carbohydrates, the body does not store protein and therefore has no reservoir to draw on when it needs a new supply.
• Vitamins and minerals are micronutrients, needed in only small quantities.

Amino Acids and Protein Types

• Proteins are made up of 20 different amino acids that join together.
• Some amino acids cannot be made by the body and are known as essential amino acids.
• It is essential that the diet provides these essential amino acids.

Measuring Total Protein

• Serum total protein is a biochemical test for measuring the total amount of protein in blood plasma or serum.
• Protein in the plasma is made up of albumin and globulin.
• Globulin is made up of α1, α2, β, and γ globulins.
• The total protein test is a faster and cheaper test that estimates the total of all fractions together.
• Other methods for measuring total protein include the Kjeldahl method, dye-binding, and refractometers.