Functional Modulation by Lactate of Myoglobin A MONOMERIC ALLOSTERIC HEMOPROTEIN

• Published in: Journal of Biological Chemistry
• Main Authors: Bruno Giardina, Giampiero De Sanctis, Menico Rizzi, Paolo Ascenzi, Massimo Coletta, Maria Elisabetta Clementi
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1996
• Subjects: Cell Biology; Molecular Biology; Biochemistry; Sperm whale
• Online Access: https://www.openaccessrepository.it/record/93443; https://doi.org/10.1074/jbc.271.29.16999

The effect of lactate on O2 binding properties of sperm whale and horse heart myoglobins (Mb) has been investigated at moderately acid pH (i.e. pH 6.5, a condition which may be achieved in vivo under a physical effort). Addition of lactate brings about a decrease of O2 affinity (i.e. an increase of P50) in sperm whale and horse heart myoglobins. Accordingly, lactate shows a different affinity for the deoxygenated and oxygenated form, behaving as a heterotropic modulator. The lactate effect on O2 affinity appears to differ for sperm whale and horse heart Mb, δlogP50 being ≈1.0 and ≈0.4, respectively. From the kinetic viewpoint, the variation of O2 affinity for both myoglobins can be attributed mainly to a decrease of the kinetic association rate constant for ligand binding.