Haem-peptide-protein interactions: Part 5. The haem undecapeptide microperoxidase-11 (Fe3+MP-11)/human serum albumin (HSA) reaction in aqueous methanolic solution. A simple system demonstrating the effect of hydrophobicity on ligand release from a ligand-protein complex.
Previous studies of the interaction of the haem undecapeptide (MP-11) with lipidated human serum albumin in aqueous solution have been extended to a range of MeOH/H2O solution compositions. It is demonstrated that the kinetic mechanism for the interaction does not change from a simple second- and first-order reversible scheme as XMeOH is increased, however while k1--the association rate constant is essentially invariant with XMeOH, K-1 increases some 600-fold over the range studied. The result is interpreted in terms of increased solvational stabilization of MP-11 and transition state as XMeOH increases and it is noted that the system provides a simple demonstration of the effect of hydrophobicity on facilitating transported ligand release from ligand/carrier protein molecules.
Adams
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Department of Chemical Pathology, University of Cape Town Medical School, Republic of South Africa.
Thumser
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D006801:Humans; D007700:Kinetics; D000432:Methanol; D010544:Peroxidases / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D012996:Solutions; D013053:Spectrophotometry
D012709:Serum Albumin; D012996:Solutions; D010544:Peroxidases; C021799:microperoxidase; D000432:Methanol