The reaction of pyridoxal 5'-phosphate (PLP) with deoxyhemoglobin is confined to 2 residues in the β chains i.e. the α-amino group of valine 1 and the ε-amino group of lysine 82, both of which are located in the polyphosphate binding site. The major product is a hemoglobin in which only the two NH2-terminal amino groups are substituted (symmetric diPLPHb). It is formed by subunit rearrangement of monoPLPHb which is the initial product of the pyridoxylation under anaerobic conditions. TetraPLPHb, with substitutions at lysine 82 and valine 1 of both β chains is found as a minor component. It results from subunit exchange of asymmetric diPLPHb consisting of one unmodified αβ dimer and one which is pyridoxylated at both sites. Anaerobic electrophoresis and oxygenation curves show that this reaction is readily reversed by mixing the tetrasubstituted derivative with unmodified hemoglobin.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Biological Chemistry|
|State||Published - 1982|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology