The hydrophobic substituent in aminophospholipids affects the formation kinetics of their Schiff bases.

Schiff bases (SBs) are the initial products of non-enzymatic glycation reactions, which are associated to some diabetes-related diseases. In this work, we used physiological pH and temperature conditions to study the formation kinetics of the SBs of 1,2-dihexanoyl-sn-glycero-3-phosphoethanolamine (DPHE) and 1,2-dihexanoyl-sn-glycero-3-phospho-l-serine (DHPS) with various glycating compounds and with pyridoxal 5'-phosphate (an effective glycation inhibitor). Based on the obtained results, the hydrophobic environment simultaneously decreases the nucleophilic character of the amino group (k1) and increases its pKa, thereby increasing the formation rate of SB (kobs).

Formation of Schiff bases of O-phosphorylethanolamine and O-phospho-D,L-serine with pyridoxal 5'-phosphate. experimental and theoretical studies.

Pyridoxal 5'-phosphate (PLP) is a B(6) vitamer acting as an enzyme cofactor in various reactions of aminoacid metabolism and inhibiting glycation of biomolecules. Nonenzymatic glycation of aminophospholipids alters the stability of lipid bilayers and cell function as a result. Similarly to protein glycation, aminophospholipid glycation initially involves the formation of a Schiff base.

Phenol group in pyridoxamine acts as a stabilizing element for its carbinolamines and Schiff bases.

Pyridoxamine (PM), a natural derivative of vitamin B(6) , possesses a high biological and biomedical significance by virtue of its acting as enzyme cofactor in amino acid metabolism and as inhibitor in the nonenzymatic glycation of proteins. Both types of processes require the initial formation of a Schiff base. In this work, we used NMR spectroscopy to study the formation mechanism for a Schiff base between PM and formaldehyde (FA).

Understanding non-enzymatic aminophospholipid glycation and its inhibition. Polar head features affect the kinetics of Schiff base formation.

Non-enzymatic aminophospholipid glycation is an especially important process because it alters the stability of lipid bilayers and interferes with cell function and integrity as a result. However, the kinetic mechanism behind this process has scarcely been studied. As in protein glycation, the process has been suggested to involve the formation of a Schiff base as the initial, rate-determining step.