Fig. 4.

NH₂-terminal acetylation of crocodilian hemoglobins (Hbs). A: MALDI-MS spectra of the α-chain subunit of Hb from Melanosuchus niger, illustrating how acetylation of the –NH₂ terminus can be detected as a 42.01-Da increase in mass of the NH₂-terminal peptide VLSPEDKANVK. B: MALDI-MS spectra of the β-chain subunit from M. niger, illustrating how acetylation of the NH₂ terminus can be detected as a 42.01-Da increase in mass of the NH₂-terminal peptide SPFSAHEEK. C: estimated extent of NH₂-terminal acetylation for the α- and β-chain subunits of adult Hbs from 6 representative crocodilian species.