[Phosphinic analog of methionine inhibits growth of leucosis cell L1210 and transforms to phosphinic analog of S-adenosylmethionine]. / Fosfinovyi analog metionina tormozit rost leikoznykh kletok L1210 i prevrashchaetsia v fosfinovyi analog S-adenozilmetionina.

A phosphinic analogue of methionine bearing a phosphinic H(OH)(O)P fragment in place of the carboxyl group inhibited the growth of the L1210 cells and was intracellularly transformed to the phosphinic analogue of S-adenosylmethionine.

[Analogs of 3'-dephospho-CoASH with a phosphodiester bond as substrates of the S-acetylation reaction, catalyzed by acetyl-CoA-synthetase fom rabbit myocardium]. / Analogi 3'-defosfo-CoASH s fosfodiéfirnoi sviaz'iu kak substraty reaktsii S-atsetilirovaniia, kataliziruemoi atsetil-CoA-sintetazoi miokarda krolika.

A number of earlier unknown 3'-dephospho-CoASH analogues with the pyrophosphate fragment replaced by an ester or phosphodiester bond were synthesized and tested in S-acetylation reaction, catalyzed by acetyl-CoA synthetase (EC 6.2.1.1) from rabbit myocardium. 3'-Dephospho-CoASH analogues with a phosphodiester bond, e.g. (Ia), had a lower affinity and diminished kinetic parameters than 3'-dephospho-CoASH (Km = 1 and 0.2 mM, respectively). The adenine substitution in (Ia) by guanine or hypoxanthine (but not cytosine) residue resulted in a loss of substrate properties. 3'-Dephospho-CoASH with an ester bond were not capable of accepting acetate under conditions used and only slightly inhibited the enzymic activity.

[Aspartyladenylate analog--effective inhibitor of asparagine synthetase]. / Analog aspartiladenilata--éffektivnyi ingibitor asparaginsintetazy.

A number of earlier unknown phosphonate analogues of aspartyl adenylate with anhydride oxygen substituted by --CH2--, and the carbonyl group substituted by --CH(OH)- or --CH(NH2)-groups were synthesized. These compounds were used to study the reaction mechanism of asparagine synthetases from white lupine and E. coli. The aspartyl adenylate analogues proved to be powerful competitive inhibitors (Ki = 10(-7) M) of the bacterial enzyme. In the case of white lupine enzyme catalyzing the aspartate-independent ATP--[32P]PPi exchange, the above compounds displayed a non-competitive type of inhibition with respect to aspartate and ATP, Ki = 10(-4) M. It is likely that for the latter enzyme the first intermediate is different from an aspartyl adenylate derivative.