Plasma protein

Plasma proteins, also known as serum proteins or blood proteins, are proteins present in blood plasma. They serve many different functions, including transport of lipids, hormones, vitamins, and minerals in activity and functioning of the immune system. Other blood proteins act as enzymes, complement components, protease inhibitors or kinin precursors.

Functions

Plasma proteins perform a wide range of functions and are critical for normal body function. Some of the key functions include:

• Transport proteins: These proteins, such as albumin and globulins, transport various substances, such as hormones, vitamins, and lipids, throughout the body.
• Immunoglobulins: Also known as antibodies, these proteins are produced by the immune system to fight off infections.
• Clotting factors: These proteins, including fibrinogen and prothrombin, are essential for the blood clotting process.
• Enzymes: Some plasma proteins act as enzymes, speeding up chemical reactions in the body.
• Complement system proteins: These proteins are part of the immune system and help or complement the ability of antibodies and phagocytic cells to clear pathogens from an organism.

Types of Plasma Proteins

There are three main types of plasma proteins: albumin, globulins, and fibrinogen.

• Albumin: This is the most abundant plasma protein and is primarily responsible for maintaining the oncotic pressure of blood.
• Globulins: These are a group of proteins that include the immunoglobulins (antibodies) and various transport proteins.
• Fibrinogen: This protein is involved in the clotting of blood.

Measurement and Clinical Significance

The levels of plasma proteins can be measured in a blood sample. Abnormal levels can indicate a variety of conditions, including liver disease, kidney disease, and malnutrition. In addition, certain types of cancer can cause elevated levels of specific plasma proteins.

See Also

• Blood plasma
• Serum (blood)
• Protein electrophoresis
• Immunoglobulin