In 1928, Todd demonstrated the production by group A streptococci of a lysine from human red blood cells. He demonstrated its antigenic character, which causes the production of circulating antistreptolysin O (ASO) antibodies after infection by the microorganism. Streptolysin O is a soluble protein of 69 kDa that binds to the erythrocyte membrane and permeabilises … Continued
Lipids are transported in serum in the form of micelles, known as lipoproteins. Lipoproteins are complex macromolecules made up of protein, cholesterol and phospholipids as external structure and esters of cholesterol and triglycerides as internal structure. Lipoproteins are classified according to their increasing density: chylomicrons, very low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins … Continued
Lipids are transported in serum in the form of micelles, known as lipoproteins. Lipoproteins are complex macromolecules made up of protein, cholesterol and phospholipids as external structure and esters of cholesterol and triglycerides as internal structure. Lipoproteins are classified according to their increasing density: chylomicrons, very low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins … Continued
Beta2-microglobulin (ß2M) is a low molecular weight protein (11.8 kD) present on the surface of many cells. beta2-microglobulin exists in two forms; in free form or in membrane form, identified as the light chain of the major histocompatibility complex (MHC) class I. Beta2-microglobulin is found in low concentrations in serum. Beta2-microglobulin is a first line … Continued
The alpha2-macroglobulin is a very large size protease inhibitor (725 kDa), primarily synthesized by cells of the hepatic parenchyma. It is involved in the inhibition of enzymes involved in the kinin-kallikrein, complement, coagulation and even fibrinolytic systems. In addition to these inhibitor roles, the alpha2-macroglobulin is used as a carrier for many small peptides (such … Continued
α1-antitrypsin, also called “α1-protease inhibitor”, is a protein of the serpin family, which is synthesised predominantly in the liver by hepatocytes. Its main role is to inhibit neutrophil elastase and thereby prevent enzyme degradation of the lung alveolar structures. It also enables the inhibition of other proteolytic enzymes such as trypsin, chymotrypsin, and thrombin. α1-antitrypsin … Continued
The alpha1-glycoprotein acid was one of the first glycoproteins to be isolated in human plasma. It contains a large number of carbohydrate moieties, giving it a very negative charge and high solubility in water. Many biological functions have been proposed for the alpha1-glycoprotein acid, but its true physiological role still remains uncertain today. The alpha1-glycoprotein … Continued
Albumin is a small protein (66.3 kDa) and the most abundant in human plasma, representing 55-65% of the total protein mass. It has different biological functions, such as the maintenance of osmotic pressure between the vascular and extravascular spaces, and the transport and storage of a wide variety of products (ions, hormones, medications, bilirubin, etc.) … Continued
