Direkte allosterische Wechselwirkung von Sauerstoff und Bicarbonat: N-Acetyl-Ala-Ser-Phe, die N-terminale Sequenz der β-Ketten der Hämoglobine des Nilkrokodils (Crocodylus niloticus) und des Mississippi­ krokodils (Alligator mississippiensis) / Direct Allosteric Interaction of Oxygen and Bicarbonate: N-Acetyl-alanyl-seryl-phenylalanine, N-Terminal Sequence of the β-Chains of the Haemoglobins of Nil Crocodile (Crocodylus niloticus) and Mississippi Crocodile (Alligator mississippiensis)

Abstract

Abstract To elucidate the molecular mechanism of the direct allosteric exchange of oxygen and hydrogen carbonate in the hemoglobins of crocodiles, the N-terminal sequence of the β-chains of the crocodiles of the Nile (Crocodylus niloticus) and of the Mississippi (Alligator mississippiensis) was studied. The N-terminal end of the peptide is blocked. By mass spectrometry the N-terminal sequences of both species were found to be N-acetyl-alanyl-seryl-phenyl-alanine. These data explain the absence of hemoglobin-phojphate interaction, the data are in good agreement with the stereochemistry postulated for allosteric exchange of oxygen and hydrogen carbonate in crocodilian hemo­ globins.