[Pyridoxal phosphate-dependent enzymes of sulfur amino acid metabolism].

Cystathionine beta-synthase and gamma-cystathionase, the two major enzymes of the transsulfuration pathway of methionine metabolism, are described. These enzymes are responsible for inborn errors, e.g.

[Interaction of acetyl-CoA-carboxylase from the rat liver with alkylating amides of ATP and ADP].

The interaction of 4-(N-chloroethyl-N-methylamino)-benzyl-gamma-amide ATP (I) and the corresponding beta-amide of ADP (II) with rat liver acetyl-CoA carboxylase was studied. Both analogs were shown to cause affinity modification of the enzyme. ATP and GoAS Ac protected the enzyme against inactivation.

[Gamma-cystathionase: the non-ideal gel filtration high performance liquid chromatography. Physico-chemical and immunochemical characteristics of the enzyme].

The rapid method for gamma-cystathionase purification was developed. It is based on the non-ideal gel filtration HPLC. The isolated homogeneous enzyme was used for immunization and immunosorbent preparation.

[Interaction of acetyl-CoA carboxylase from the rat liver with analogs of activated carbon dioxide and ATP].

The interaction of rat liver Ac-CoA-carboxylase with reactive and stable analogs of carbon dioxide and phosphoric acid mixed anhydrides--hypothetic intermediate of the enzyme reaction--has been studied. Carbamoylphosphate showed substrate properties, whereas phosphonacetic acid and beta-oxopropyl-alpha, alpha-diphosphonate inhibited this enzyme (Ki 3.0 and 3.

[Organophosphate analogs of biologically active compounds. XIV. Halophosphonate analogs of ATP as acetyl CoA carboxylase inhibitors].

Halophosphonate ATP analogues pp[CHBr]pA and p[CHBr]ppA synthesised from bromomethylenebisphosphonate and adenosine derivatives, proved to be effective competitive inhibitors of Ac-CoA-carboxylase (CE 6.4.1.

[Purification of homogeneous gamma-cystathionase and study of its structure by circular dichroism].

Rat liver gamma-cystathionase has been purified to homogeneity (verified by SDS electrophoresis and ultracentrifugation). The secondary and tertiary structures of the enzyme were studied by circular dichroism spectra. Our studies revealed that the holoenzyme molecule comprises approximately 22% of alpha-helices, 14% of beta-structure, 14% of beta-bends, and 50% of unordered structure.

[Role of beta-cyanoalanine hydratase in the synthesis of asparagine in white lupine].

A highly active beta-cyanoalanine hydratase catalyzing the asparagine synthesis from beta-cyanoalanine was isolated from 11-day-old etyolated seedlings of white lupine (Lupinus albus) and subjected to purification. In white lupine seedlings the enzyme activity is 300 times as high as that in extracts of blue lupine (Lupinus angustifolius). The experimental data suggest that in white lupine seedlings asparagine synthesis from cysteine and cyanide occurs via beta-cyanoalanine production with its subsequent hydratation.

[Artifactual multiple forms of beta-cyanoalanine synthase from white lupine].

The three active forms of beta-cyanoalanine synthase (EC 4.4.1.

[Beta-cyanoalanine synthase from white lupin: some catalytic properties].

Highly purified beta-cyanoalanine synthase was prepared from 11-day-old etiolated sprouts of white lupine in the presence of diisopropylfluorophosphate. The enzyme preparations were homogeneous during polyacrylamide gel electrophoresis; their specific activity exceeded that of the blue lupine enzyme 100-fold. The purification procedure included preparation of mitochondrial acetonated powder, isolation of enzyme, chromatography on DEAE-Sephadex A-50, fractionation on Sephadex G-100 and preparative polyacrylamide gel electrophoresis.

[Isolation and some properties of immobilized cystathionine-beta-synthase].

Covalent binding of the pyridoxal phosphate-dependent lyase--cystathionine-beta-synthase from chicken liver--by CNBr-activated Sepharose 4B and 6B resulted in catalytically active preparations of immobilized enzyme. Immobilized cystathionine-beta-synthase was shown to possess a higher stability as compared to the native enzyme. The maximum of activity of the obtained preparations was revealed at high temperatures (63 degrees), whereas the native enzyme had the temperature optimum at 40 degrees.

[Steady-state kinetics of reactions catalyzed by serine sulfhydrases of Saccharomyces serevisiae].

The steady-state kinetics of the two substrate reaction of L-cysteine desulfation in the presence of 2-mercaptoethanol catalyzed by serine sulfhydrase from bakers yeast -- a pyridoxal phosphate-containing enzyme of the beta -- substituting lyase type -- were studied. Highly purified enzyme preparations (approximately 90% purity) of Saccharomyces cerevisiae with specific activity of 25 mumoles of H2S per 1 hr per mg of protein were used. The values of V, KS1, KS2 and alpha were calculated from the initial rates of the reaction under constant concentration of L-cysteine (S1) and variable concentration of 2-mercaptoethanol (S2) and vice versa.

[Alliinase: purification and chief physico-chemical properties].

A method has been developed for the purification of alliinase from garlic bulbs. High purity preparations of the enzyme were obtained with specific activity increased 67-fold over that of the homogenate. The preparations were homogeneous on electrophoresis in polyacril gel.

[Resolution of beta-cyanoalanine synthase and recombination of its apoenzyme with pyridoxal-5'-phosphate and its analogs].

A procedure is described for the resolution of beta-cyanoalanine synthase (E.C.4.

[Beta-cyanoalanine synthase: Its purification and basic physico-chemical properties].

A method has been developed for the purification of beta-cyano-L-alanine synthase from etiolated 10-day-old seedlings of blue lupine. High purity preparations of the enzyme were obtained with specific activity exceeding 4000-fold that of the seedling homogenate. Preparations were homogeneous on electrophoresis in polyacrylamide gel.

[Substrate specificity of cysteine lyase].

Substrate specificity is studied of cysteine lyase, a phosphopyridoxal-dependent enzyme belonging to the subgroup of beta-replacing lyases. This enzyme has a narrow specificity for the amino substrate; its only primary substrate is L-cysteine. Cysteine lyase has a broad specificity for the cosubstrate (replacing agent), catalysing the synthesis of L-cysteic acid from L-cysteine and sulfite ion or cystein thioesters (in the presence of some thiols).