[Two forms of carbonic anhydrase from bean chloroplasts]. / Dve formy karboangidrazy v khloroplastakh bobov.

The intracellular localization of carboanhydrase from the bean (Vicia faba) leaves was investigated. The bulk of the enzyme activity (about 70%) is localized in the chloroplasts. The enzyme exists both in the soluble and in membrane-bound state. Disc electrophoresis in polyacrylamide gel with specific staining for the enzyme activity demonstrated that the soluble and membrane-bound carboanhydrases from bean chloroplasts are two molecular forms (presumably isoenzymes) differing in their electrophoretic mobilities. Protein fractionation with (NH4)2SO4 and a subsequent gel filtration on Sephadex G-200 and isoelectrofocusing resulted in separation of the two forms and their purification to homogeneity. Both carboanhydrases differ in pH, specific activity and stability.

[Carboanhydrase from bean leaves]. / Karboangidraza iz list'ev bobov.

A highly purified preparation of carboanhydrase from the leaves of the bean Vicia faba var. major (Harz) F. Janthina was obtained. The enzyme was homogeneous during analytical disc-electrophoresis in polyacrylamide gel and analytical ultracentrifugation. The molecular weight of the enzyme is 270,000. The enzyme molecule contains six Zn atoms, has a quaternary structure and is made up of six subunits with molecular weights of 45,000. Some properties of the enzymes from bean leaves and pea leaves were compared. The enzymes differ in molecular weights and behaviour during DEAE-cellulose chromatography and gel filtration through Sephadex G-200.

[Multiple molecular forms of ribulose diphosphate carboxylase from mung bean leaves]. / Mnozhestvennye molekuliarnye formy ribulozodifosfat-karboksilazy iz list'ev masha.

Ribulose diphosphate carboxylase from Phaseolus aureus leaves is represented by four molecular forms differing in their carboxylase and oxygenase activities, molecular weights, sedimentation coefficients, electrophoretic mobilities in polyacrylamide gel, chromatographic behaviour upon elution on Sephadex G-200 and DEAE-cellulose, pH optima of carboxylase activity and pI values. In some parameters, e. g. molecular weight of the whole molecule (530 000), molecular weights of the large and the pH optima of the carboxylase and oxygenase activities (8.5 and oxygenase activities (2.4 and 0.09 units per mg of protein, respectively) and the pH optima of the carboxylase and oxygenase activities (8.5 and 9.3, respectively) form II differs from form I, which has a lower molecular weight (480 000), a higher oxygenase and a lower carboxylase activities (0.2 and 1.5 units per mg of protein, respectively) and a higher pH optimum of the carboxylase activity (9.0). Both forms I and II are composed of eight large and eight small subunits. The molecular weight of the large subunits of form I is lower than that of form II and is equal to 48 000. The respective pI values for forms I and II are 6.8 and 6.4. Forms III and IV as well as forms I and II produce distinct bands under ion-exchange chromatography on DEAE-cellulose. The carboxylase and oxygenase activities of form III are 0.7 and 0.04 units per mg of protein, respectively. Form IV has a higher oxygenase and a lower carboxylase activity (0.09 and 0.25 units per mg of protein, respectively). The corresponding molecular weights of forms III and IV are 530 000 and 480 000. The molecular weights of the large and small subunits of form II are 53 000 and 12 000, respectively; those of form IV -- 48 000 and 12 000, respectively.

[Properties and quaternary structure of ribulosediphosphate carboxylase from the leaves of Elymus (Psathyrosachys) junceus]. / Svoistva i chetvertichnaia struktura ribulozodifosfatkarboksilazy iz list'ev volosnetsa sitnikovogo.

The enzyme ribulosdiphosphate carboxylase was isilated from the leaves of Elymus (Psathyrosachys) junceus. The enzyme was found homogenous during disc-electrophoresis in polyacrylamide gel and analytical ultracentrifugation. The sedimentation coefficient for the enzyme is 17,4S. The enzyme molecular weight as determined by the sedimentation equilibrium technique is equal to 540000. The enzyme molecule consists of 2 types of subunits, i.e. the larger subunit has m.w. of 55000, the smaller one--12900. The number of large subunits is 8, that of small ones--8. The specific activity of the homogenous enzyme makes up to 2,45 mkmoles of CO2 per min per mg of protin (pH 8,0, 30 degrees). The purified enzyme was stable in Mg2+- and dithiothreitol-containing buffers for 3--4 weeks at 4 degrees and for 5--6 months at --20 degrees. The amino acid composition of the enzyme molecule is similar to that of the enzyme from spinach leaves.

[Effect of growth conditions on the activity of the enzymes of cyclic 3':5'-AMP synthesis and decay in phototrophic bacteria]. / Bliianie uslovii byrashchivaniia fototrofnykh bakterii na aktivnost' Fermentov sinteza i raspada tsiklicheskogo 3':5'-AMP.

Activity, ratio and summary content of cyclic AMP enzymes, adenylate cyclase and phosphodiesterase varied depending on growth conditions of phototrophic bacteria (Rhodospirillum rubrum and Rhodopseudomonas palustris). It suggests, that membrane-bound and soluble enzymes carry different functions. The increase of adenylate cyclase under chaning growth conditions was usually accompanied by the increase of phosphodiesterase. Sharp increase of both enzymes activity was observed when bacteria were growth in aerobic conditions. The activity of both enzymes in chromatophores was 2.8-fold higher when bacteria were grown in the light in anaerobic conditions, than in chromatophores of bacteria grown under stationary aerobic conditions in the light. It is suggested that 3':5' AMP can participate in autotrophic carbon assimilation or in the synthesis of pigments and other components of bacterial photosynthetizing apparatus. Substitution of NH4+ into NO3- and glutamate under the growing of R. rubrum in anaerobic conditions in the light resulted in the increase of the enzymes activities, which is the evidence of possible role of 3':5' AMP in mineral nitrogen uptake and nitrogen fixation. Glutamate concentration of 4 g/l stimulated the enzymes both in vivo and in vitro. The data obtained suggest that 3':5' AMP can carry multiple functions, participating in regulation of a number of metabolic processes in photorophic bacteria.

[Subcellular distribution and several properties of the cAMP enzyme system of phototrophic bacteria]. / Subkletochnoe raspredelenie i nekotorye svoistva fermentov sistemy cAMP u fototrofnykh bakterii.

In the cells of the phototrophic bacteria Rhodospirillum rubrum and Rhodopseudomonas palustris the two enzymes of the cAMP system enzymes - adenylate cyclase and cAMP phosphodiesterase (PDE) exist in a soluble and membrane-bound forms. After mild disruption of the cells (sonication up to 3 min) the activity of both enzymes is found in the chromatophores. In the cells of the two types of bacteria grown under anaerobic conditions soluble adenylate cyclase is predominant. In the cells of R. rubrum the soluble form of PDE posesses higher activity, whereas in the cells of Rh. palustris a higher activity is observed in the membrane-bound form. In addition to their different localization in the cells, the PDE forms of Rh. rubrum differ in their ratios to the concentrations of hydrogen ions and bivalent metals; the latter difference, however, may be accounted for by the effect of a protein modulator of PDE. The pH optimum of membrane-bound PDE is 9.15. Soluble PDE has two activity maxima at pH 7.5 and 8.7. It is probable that similar to the animal tissue enzyme, PDE from Rh. rubrum exists in the soluble phase in at least tw forms. Close pH optima for soluble adenylate cyclase and for one of the soluble PDE forms (about 8.5) may indicate the unidirectional control of these enzymes by hydrogen ion concentration.

[cAMP phosphodiesterase from phototrophic bacteria Rhodospirillum rubrum]. / Fosfodiesteraza 3',5'-AMP Fototrofnoi bakterii Rhodospirillum rubrum

cAMP phosphodiesterase activity is discovered in supernatant of R. rubrum cell homogenate after centrifugation at 1000 g. The enzyme is highly active (5.62 nmoles/mg of protein per 1 min) at a broad pH range--from 7.0 to 9.0. The enzyme activity is strongly inhibited with caffeine and dithiotreitol and very significantly inhibited by ascorbic acid. The dependence of the enzyme activity on the incubation time and protein and substrate concentrations in the reaction mixture is estimated. cAMP phosphodiesterase is found in soluble fraction and in particule fractions sedimenting at 30 000 g. The enzyme activity is completely absent in washed chromatophores sedimenting at 160 000 g.

[Carbonic anhydrase of blue-green alga Spirulina platensis]. / Karboangidraza sine-zelenoi vodorosli Spirulina platensis

Carboanhydrase (carbonate-hydroliase EC 4.2.1.1.) is found in the extract of Spirulina platensis cells. A linear dependency of the enzyme activity on the protein concentration; pH optimum is found to be 8.0. Specific activity of carboanhydrase is 3 muM/min-mg of protein under the concentration of CO2 of 4-10(-3) M, appearing Michelis constant being 4.9-10(-3) M. The enzyme was stabilized with 10 mM of cisteine, its activity was inhibited by 50% with sulphanylamide (1-10(-5) M), acetazolamide (8--10(-7) M) and Cl- ions (5-10(-2) M). The activity of carboanhydrase, as well as the rate of NaH14CO3 fixation, depended on the pH value of cultural medium.