Bilirubin Dyes

Bilirubin is a type of bile pigment. It is the main pigment in human bile and is orange-yellow. Bilirubin is the main metabolite of iron porphyrin compounds in the body. It is toxic and can cause irreversible damage to the brain and nervous system, but it also has an antioxidant function that can inhibit the oxidation of linoleic acid and phospholipids. Bilirubin is an important basis for judging jaundice clinically and an important indicator of liver function.

Introductions

Bilirubin is a bile pigment of biladiene. It is red-brown pigment body, insoluble in water, hardly soluble in alcohol, ether, and easily soluble in alkali. The maximum absorption is 432 nm (in alkali) and 540 nm (in chloroform). Bile is abundant in humans and carnivores. Blood bilirubin, in the red-purple Hijman van den Bergh reaction caused by the addition of diazo reagents, there are two types: one is a direct type that appears positive without alcohol, and the other is an alcohol Indirect color rendering. The first type is mono- or di-glucuronic acid (ester), and the second type is free. It is a normal metabolite of hemoglobin. It can be formed by reduction of bilirubin. If further reduced, it is converted to ethyl by vinyl Mesobilirubin C30H40O6N, all methine is saturated with hydrogen, forming mesobilirubinogen (urobilinogen). Bilirubin is a pigment made by hemoglobin in red blood cells. Red blood cells have a fixed life span (the average life expectancy of normal red blood cells is about 120 days) and is destroyed every day. At this time, hemoglobin is broken down into haem and heme. Methionin produces bilirubin under the action of NADPH and H ions. Trivalent Fe ions and CO, and bilirubin produces bilirubin under the action of NADPH and H ions. Heme is then reconstituted into tissue protein.

Structure and functions

Bilirubin is composed of ring-opened tetrapyrrole. It is formed by the oxidative cleavage of porphyrins in heme, thus providing biliverdin. Biliverdin is reduced to bilirubin. When combined with glucuronic acid, bilirubin is excreted. Bilirubin is structurally similar to the pigment phycocyanin used by some algae to capture light energy, and the pigment plant pigment used by plants to sense light. All of them contain an open chain of four pyrrole rings. Like other pigments, some double bonds in bilirubin areomerized when exposed to light. This isomerization is related to the phototherapy of jaundice newborns: the E and Z isomers of bilirubin formed during exposure are more soluble than the unirradiated Z and Z isomers because the possibility of intramolecular hydrogen bonding is eliminated Sex. Increased solubility excretes unbound bilirubin in bile. Some textbooks and research articles indicate that the geometric isomers of bilirubin are incorrect. The naturally occurring isomers are Z, Z-isomers.

Bilirubin Dyes Figure 1. Structure of Bilirubin.