[Distribution of pyridoxal-5-phosphate between proteins and low molecular weight components of plasma: effect of acetaldehyde].
It is found that approximately 65-70% of pyridoxal-P at physiological concentrations is bound to plasma proteins; 15% of its amount is bound to amino acids and peptides as a result of the Schiff base formation. Over 85% of pyridoxal-P associated with plasma proteins is bound to serum albumin. Inorganic phosphate and NaCl decrease the affinity of pyridoxal-P for albumin or other proteins. Acetaldehyde interacts with the alpha-amino group of the aspartic acid residue of the N-end of the polypeptide chain of the albumin molecule and with two epsilon-amino groups of the lysine residues having anomalously low value of pKa and deprotonated at physiological values of pH of the medium. Acetaldehyde competes with pyridoxal-P for the first (of the highest affinity) binding site of the coenzyme on serum albumin. Acetaldehyde is not bound at the second site of high affinity for pyridoxal-P on serum albumin.
Stepuro
I I
II
Solodunov
A A
AA
Piletskaia
T P
TP
Iaroshevich
N A
NA
Ostrovskiĭ
Iu M
IuM
D000079:Acetaldehyde / Q000494:pharmacology*; D000596:Amino Acids / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D004589:Electrophoresis, Disc; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008970:Molecular Weight; D010949:Plasma / Q000378:metabolism*; D011485:Protein Binding; D011730:Pyridoxal / Q000097:blood; D011732:Pyridoxal Phosphate / Q000097:blood*; D013050:Spectrometry, Fluorescence
D000596:Amino Acids; D001798:Blood Proteins; D011730:Pyridoxal; D011732:Pyridoxal Phosphate; D000079:Acetaldehyde
Raspredelenie piridoksal'-5-fosfata mezhdu belkami i nizkomolekuliarnymi komponentami plazmy krovi: vliianie atsetal'degida.