PLP acts as a coenzyme in all transamination reactions, and in certain decarboxylation, deamination, and racemization reactions of amino acids.The aldehyde group of PLP forms a Schiff-base linkage (internal aldimine) with the ε-amino group of a specific lysine group of the aminotransferase enzyme. The α-amino group of the amino acid substrate displaces the ε-amino group of the active-site lysine residue in a process known as transaldimination. The resulting external aldimine can lose a proton, carbon dioxide, or an amino acid sidechain to become a quinoid intermediate, which in turn can act as a nucleophile in several reaction pathways. In transamination, after deprotonation the quinoid intermediate accepts a proton at a different position to become a ketimine. The resulting ketimine is hydrolysed so that the amino group remains on the complex.
In addition, PLP is used by aminotransferases (or transaminases) that act upon unusual sugars such as perosamine and desosamine. In these reactions, the PLP reacts with glutamate, which transfers its alpha-amino group to PLP to make pyridoxamine phosphate (PMP). PMP then transfers its nitrogen to the sugar, making an amino sugar.
PLP is also involved in various beta-elimination reactions such as the reactions carried out by serine dehydratase and GDP-4-keto-6-deoxymannose-3-dehydratase (ColD).It is also active in the condensation reaction in heme synthesis.
PLP plays a role in the conversion of levodopa into , facilitates the conversion of the excitatory neurotransmitter glutamate to the inhibitory neurotransmitter GABA, and allows SAM to be decarboxylated to form propylamine, which is a precursor to polyamines.
1) Pyridoxal-5-Phosphate is used to treat Parkinson's disease 2) Promote the transaminase in transamination levels in the body 3) Used in the treatment of acute or chronic eczema dermatitis nettle examine pustular rash itching seborrheic eczema scaly rash drug eruption deficiency oral inflammation glossitis pregnancy reaction, asthma, etc 4) The main body of vitamin B6
