Department of Physiological Chemistry, Karolinska Institutet, Stockholm, Sweden.
Peptide generation and fast atom bombardment mass spectrometry in combination with conventional chemical analysis was used to identify the blocking group and establish the N-terminal structure of six different proteins at the nanomole level. In this manner, the first terminal structures of three non-mammalian alcohol dehydrogenases were determined, demonstrating the presence of N-terminal acetylation in these piscine, amphibian, and avian enzymes. Similarly, two different yeast glucose-6-phosphate dehydrogenases and a minor variant of a human alcohol dehydrogenase were found to be acetylated. The exact end location of C-terminal structures was also established. Together, the analyses permit the definition of terminal regions and blocking groups, thus facilitating the delineation of remaining structures.