[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.

Peptide sequencing by partial acid hydrolysis and high resolution plasma desorption mass spectrometry.

A method of deriving peptide sequence information using partial acid hydrolysis in combination with accurate mass measurements and immonium ion analysis provided by high-resolution plasma desorption mass spectrometry has been developed. The technique is very simple in terms of the chemistry and involves a short-time (3-30 min) incubation of the peptide in 1N-6N HCl at 100-110 degrees C with subsequent mass spectrometric analysis. Partial acid hydrolysis is found to produce sequence-specific segments, often ladder-like, although not always a complete set. Two application examples of the method are given: the linear peptide bradykinin and desmopressin, a peptide with an internal S-S bond and a non-amino-acid constituent. The technique has proved to be particularly useful in cases where some a priori information on the peptide structure was already known or where the automated Edman degradation technique might yield erratic results or not work at all.

[Use of time-of-flight mass spectrometry with ionization division fragments of californium-252 for studying the mechanisms of action of drugs on DNA and its components]. / Primenenie vremia proletnoi mass-spektrometrii s ionizatsiei oskolkami deleniia kaliforniia-252 k izucheniiu mekhanizmov deistviia lekarstvennykh preparatov na DNK i ee komponenty.

Using soft-ionization mass spectrometry (252-Cf particle desorption mass spectrometry, PDMS) a minor adduct of anticancer drug prospidine and deoxyguanosine-5-phosphate (pdG) has been found. It has been shown experimentally that PDMS is very useful for study of biological mixtures as well as mechanisms of interactions between drugs and biomolecules.

Study of anticancer drug interaction with DNA by means of particle-induced desorption mass spectrometry: prospydine and deoxyguanosine-5'-monophosphate.

Using 252CF particle desorption mass spectrometry, the interaction between an antitumour drug prospydine (Pro) and deoxyguanosine-5'-monophosphate (pdG) has been studied. The adduct which corresponds to a peak at m/z 524.5 and which occurs as a result of the particular degradation of Pro during its alkylating of pdG has been found.

[Study of the interaction of triethylenethiophosphamide with nucleotides by mass spectrometry with ionization by fission fragments of californium-252]. / Izuchenie vzaimodeistviia triétilentiofosfamida s nukleotidami metodom mass-spektrometrii s ionizatsiei oskolkami deleniia kaliforniia-252.

Study of interaction of the antitumor alkylating drug triethylenethiophosphoramide (thioTEPA) with nucleotides (dGMP and dCMP) suggests highly perspective employment of 252-Cf fission fragment induced desorption mass spectrometry (252-Cf PDMS) in biochemical pharmacology. Using the 252-Cf PDMS the molecular masses of the unstable, unvolatile, high-molecular substances of biological origin and the chemical adducts or complexes with drugs can be used to establish some structural-functional parameters of the above mentioned biomolecules and their derivatives in microvolumes of the incubation medium. The resulting data may be used for modelling chemotherapeutic processes of "drug-biomolecule-target" type. Using 252-Cf PDMS the complexes (dGMP (thioTEPA) n), n = 1, 2, 3 and (dCMP (thioTEPA) n), n = 1, were obtained. Some quantitative parameters and stability of these complexes were studied. Binding of dGMP with drug in the presence of dCMP was shown preferential. The data are compatible with the predictions concerning the mechanism of the antitumor property of the thioTEPA which can be manifested in the impairment structure of DNA of the malignant cells.

[The effect of growth marker proteins on the ionic permeability of rabbit liver mitochondria]. / Vliianie belkov-markerov rosta na ionnuiu pronitsaemost' mitokhondrii pecheni krolika.

The growth marker proteins from blood serum of new-born rabbits and G-myeloma-bearing people were studied for their effect on ionic permeability of rabbit liver mitochondria. The proteins under study induce an increase in nonspecific ionic permeability and swelling of mitochondria. Thiol compounds, in particular CoA8H (in small concentrations) neutralize the effect of growth marker proteins on the bioenergetic characteristics of mitochondria and lower considerably the protein-induced nonspecific ionic permeability.

[Effect of protein-markers of growth on oxidative phosphorylation in mitochondria]. / Vliianie belkov-markerov rosta na okislitel'noe fosforilirovanie v mitokhondriiakh.

Growth marker proteins (GMP) were studied for their effect on oxidative phosphorylation in the heart and liver mitochondria of rabbits. It is shown that GMP decrease a respiratory control (RC) coefficient, P/O coefficient, inhibit respiration of the mitochondria in metabolic states 3, 5 and activates it in state 4. The nature of the oxidation substrates (FAD- and NAD-dependent succinic and pyruvic acids, respectively) does not influence the GMP effect manifestation. It is supposed that GMP disturb the structural and functional integrity of the mitochondria. Variations in bioenergetic parameters of the heart and liver mitochondria in organisms with active growth foci as well as of mitochondria incubated with GMP, are unidirectional. Cytochrome c, coenzyme A (Co ASH) and other thyol compounds (cystein, dithiotreitol, glutathione--GSH) remove the GMP action.

[Effect of various respiration substrates and growth marker proteins on oxygen consumption in rabbit heart mitochondria]. / Vliianie razlichnykh substratov dykhaniia i belkov markerov protsessov rosta na pogloshchenie kisloroda mitokhondriiami serdechnoi myshtsy krolikov.

Oxygen uptake by myocardium mitochondria of healthy, carcinomatous and new-born rabbits in the presence of different substrates was studied under the effect of immunoglobulin G and beta-globulin peculiar to the normal and malignant growth. It is stated that the growth marker proteins representing a subfraction of immunoglobulin G of tumour patients blood serum and beta-globulin of new-born rabbits blood serum in the presence of pyruvate, alpha-ketoglutarate and glutamate inhibit the oxygen uptake by healthy rabbits heart mitochondria. Studies conducted on mitochondria of new-born and carcinomatous rabbits show that the action of the proteins under study depends on the respiration substrate. In the presence of succinate the proteins under study activate the oxygen uptake and pyruvate, alpha-ketoglutarate and glutamate inhibit this process. A conclusion is drawn that the effect of proteins peculiar to the growth process on the biological oxidation depends both on the substrate and structural state of mitochondria.