What Is a Flavoprotein?

Flavoproteins (FPs) are enzymes composed of one polypeptide bound to one prosthetic group, and are not fat-soluble. The bound prosthetic group can be FAD or FMN, which are derivatives of vitamin B2. Each FMN and FAD can accept two electrons and two protons. NADH dehydrogenase with FMN as a prosthetic group on the respiratory chain. ^[1]

Flavoprotein

Right!

Flavoproteins (FPs) are enzymes composed of one polypeptide bound to one prosthetic group, and are not fat-soluble. The bound prosthetic group can be FAD or FMN, which are derivatives of vitamin B2. Each FMN and FAD can accept two electrons and two protons. NADH dehydrogenase with FMN as a prosthetic group on the respiratory chain. ^[1]

Flavoproteins are enzymes composed of a polypeptide bound to one prosthetic group, not fat-soluble. The bound prosthetic groups can be FAD or FMN, which are derivatives of vitamin B2, each prosthetic group can accept and provide two protons and electrons.

There are many types of flavin proteins. There are two types of prosthetic groups, one is flavin single nucleotide (FMN), and the other is flavin adenine dinucleotide (FAD).

FAD or FMN and the enzyme protein are connected by non-covalent bonds, but the binding is strong, so oxidation and reduction (ie, loss and gain of electrons) are performed on the same enzyme protein, so the oxidation of flavin nucleotide The reduction potential depends on the protein that binds them, so the relevant standard reduction potential refers to the specific flavin protein, not the free FMN or FAD; they are only in the active center part of the flavin protein in the electron transfer reaction, and It cannot be used as a substance or product itself. This is different from NAD +. NAD + loosely binds to an enzyme protein. When it binds to an enzyme protein, it can receive hydrogen from metabolites and be reduced to NADH. This enzyme protein binds and is oxidized to NAD + after releasing hydrogen. The isopyrazine moiety in the FAD and FMN molecules can undergo a reversible dehydrogenation reaction.

Most flavin proteins are involved in the composition of the respiratory chain and are related to electron transfer. For example, NADH dehydrogenase (NADh dehydrogenase) uses FMN as a prosthetic group and is one of the components of the respiratory chain, which is between NADH and other electron transporters; amber Acid dehydrogenase, the auxiliary group of glycerol phosphate dehydrogenase in mitochondria is FAD, which can directly transfer the reduction equivalent H ++ e reducing equivalent from the substrate to the respiratory chain, and in addition, fatty acyl CoA dehydrogenation Enzymes are similar to succinate dehydrogenases. They are also flavin proteins with FAD as a co-group. They can also transfer reducing equivalents from the substrate to the respiratory chain, but another electron transporter is needed in the middle, called an electron transfer flavin protein. (Electron? Transferring flavo? Protein, ETFP, prosthetic group is FAD) participation can be completed.