[Mass spectrometry in the study of bioclasters of amino acids and peptides]. / Issledovanie bioklasterov aminokislot i peptidov metodom mass-spektrometrii.

The study of homo- and heterocluster quasimolecular ions of 20 L-amino acids (A) and five dipeptides by the TOF-PDMS method indicated that the intensity of quasimolecular ions of the corresponding homo-([An + H]+ and [Bm + H]+, where A and B are biomolecules (A, dipeptides), n and m = 1 .... 5) and heteroclusters ([An.Bm + H]+, n and m = 1 .... 5) depends mainly on the hydrophobicity of the constituents of the A cluster. The most intensive peaks of homo- and heterocluster ions were obtained for hydrophobic amino acids: L-Ile, L-Leu, L-Val, and L-Phe, and for dipeptides containing these amino acids. The assumption is made that the stereochemical parameters of heterocluster quasimolecular ions in the TOF-PDMS method are determined by the physicochemical mechanisms involved in the processes of ionization/desorption of biomolecules and do not reflect directly biologically significant interactions of biomolecules in vivo.

[An improved method of preparing protein and peptide probes in mass spectrometry with ionization of division fragments by californium-252 (TOF-PDMS)]. / Usovershenstvovanniia metodika podgotovki prob belkov i peptidov v mass-spektrometrii s ionizatsiei oskolkami deleniia kaliforniia-252 (TOF-PDMS).

The addition of organic acids (picric, oxalic, citric, or tartaric) to peptide and protein samples was found to significantly increase the yield of their quasi-molecular ions (QMI) in time-of-flight 252Cf plasma desorption mass spectrometry. The yield of the ions depended on the pKa of the acid added.