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H Kindl

Publications and source records attributed to H Kindl.

At least 73 records · Page 4Linked to original sources
PubMed1979

Albumins, glyoxysomal enzymes and globulins in dry seeds of cucumis sativus: qualitative and quantitative analysis.

1) Albumins and globulins were prepared from dry seeds of cucumbers (Cucumis sativus) by differential extraction. The globulin fraction was analyzed by gel electrophoresis under denaturing conditions in the presence and absence of mercaptoethanol. The subunit (Mr = 54000) of the tetramer (Mr = 240000) was shown to be composed of two different peptides. Microheterogeneity rendered the exact interpretation of the analysis difficult. 2) Glyoxysomal proteins were already present in dry seeds: malate synthase, isocitrate lyase, citrate synthase, malate dehydrogenase, catalase and crotonase could be detected unequivocally. It was demonstrated that the enzymatic and immunological properties of malate synthase and isocitrate lyase were not distinguishable from that of enzymes assigned to glyoxysomes of fully developed cotyledons. 3) Homogenates prepared from seeds by cautious cell disintegration were subjected to sucrose density gradient centrifugation and yielded microbody and protein body fractions, among other things.

Albumins↗
PubMed1979

Plant plasma membrane. Correlation between glucan synthase II activity and a mannosyl transferase activity.

In cotyledons of germinating cucumber seeds (Cucumis sativus), plasma membranes were investigated biochemically and partially characterized. Glucan synthease II was utilized as a marker to locate plasma membrane vesicles within fractions obtained by differential centrifugation or within sucrose gradients used either in zonal centrifugations or in sedimentations to equilibrium density. Thorough homogenization led to a homogeneous population of plasma membrane vesicles which could be clearly separated from mitochondria by centrifugation at 150000 x g for 4 h in a zonal rotor. The profiles of glucan synthase II activity and naphthylphthalamic acid binding coincided with that of a mannosyl transferase activity, monitored by direct transfer of mannose from GDPmannose to endogeneous acceptors.

Cell Fractionation↗
PubMed1979

Rates of de novo synthesis of malate synthase and albumins during the very early phase of germination.

Malate synthase is synthesized de novo in the very phase of germination. Its molecular and immunological properties do not differ from those of malate synthase from fully developed cotyledons. Radioactive leucine was administered to dry seeds of cucumber, and its incorporation into proteins of cotyledons was examined after 2 days of germination. The specific radioactivity of malate synthase, purified by immunoprecipitation and electrophoresis on polyacrylamide gel, was only 1/20 the average value of the total albumin fraction. The minimal incorporation documented by the comparatively low specific activity of isolated malate synthase is discussed in relation to the large pool of malate synthase already present in dry seeds.

Albumins↗
PubMed1978

Plant microbody proteins. Purification and glycoprotein nature of glyoxysomal isocitrate lyase from cucumber cotyledons.

1. Isocitrate lyase from cotyledons of cucumber seedlings (Cucumis sativus) has been purified 100-fold. Two methods of preparing the soluble glyoxylate cycle enzyme are described: an elaborated method which used crude extracts of cucumber cotyledons, and another procedure which started with purified glyoxysomes from 4-day-old cotyledons and included a separation of glyoxysomal matrix enzymes by zonal centrifugation. The product behaved as a single species when tested by (a) polyacrylamide gel electrophoresis in the presence of dodecyl sulfate, (b) zonal centrifugation, and (c) double immunodiffusion against rabbit antibody to isocitrate lyase. 2. Isocitrate lyase of cucumber glyoxysomes exhibited a molecular weight of 255,000 and was composed of four apparently identical subunits of Mr 64,000. An isoelectric point of 5.9 was determined. 3. It was shown that isocitrate lyase is a glycoprotein, (a) by Schiff stain on polyacrylamide gels, (b) by periodate oxidation of the enzyme, subsequent reduction with NaB[3H]4 and electrophoretic analysis of the labelled glycoprotein, and (c) by incorporation of [3H]glucosamine in vivo into a protein which could be precipitated with antibodies to isocitrate lyase and revealed a 64,000-Mr band upon electrophoresis.

Carbohydrates↗
PubMed1978

Stilbene synthases and stilbenecarboxylate synthases, I Enzymatic synthesis of 3,5,4-trihydroxystilbene from p-coumaroyl coenzyme A and malonyl coenzyme A.

1) Cell-free extracts prepared via acetone powder from rhizome of Rheum rhaponticum were found to be capable of converting p-coumaroyl-CoA and [2-14C]malonyl-CoA into a 3,5,4'-trihydroxystilbene, resveratrol. The product was characterized by repeated chromatography and by recrystallization to constant specific radioactivity. 2) The mode of condensation of the phenylpropanoid moiety with C2 units was determined by chemical degradation of the enzymatically formed product. 3) The enzyme system which catalyses the condensation of p-coumaroyl moiety with 3 malonyl units, the intramolecular aldol reaction and the subsequent decarboxylation was classified as stilbene synthase. It could be activated by dithiothreitol. 4) When the extraction of the rhizome was performed with aqueous grinding medium, a high percentage of this stilbene synthase activity was found to be membrane-bound.

Catalysis↗
PubMed1976

Plant microbody proteins, I. Purification and characterization of catalase from leaves of lens culinaris.

1) Catalase from green leaves of Lens culinaris (lentils) was investigated with respect to isoenzyme patterns. In contrast to other plants, which have been reported to contain multiple forms of catalase, only one form of this enzyme was revealed when crude extracts were subjected to starch gel electrophoresis or to polyacrylamide disc-gel electrophoresis. Furthermore, catalases from leaves, stems and cotyledons were electrophoretically identical. 2) The leaf enzyme has been purified by conventional methods to apparent homogeneity. It has a molecular weight of 225 000 (ultracentrifuge) and is composed of four identical subunits of molecular weight 54 000 (sodium dodecylsulphate gel electrophoresis). The ratio A280/A405 of the pure enzyme was found to be 1.5. The isoelectric point is at pH 5.5. The enzyme, very labile at pH-values below 7.0, is stable in Tris chloride and potassium phosphate buffers between pH 7.5 and 9.5. It is slowly inactivated by 1mM dithiothreitol and is rapidly inactivated by 1mM mercaptoethanol. 3) The catalase was shown to be the major protein component of the peroxisomal matrix. It could not be detected at the membranes of the leaf peroxisomes.

Catalase↗
PubMed1976

Plant microbody proteins. II. Purification and characterization of the major protein component (SP-63) of peroxisome membranes.

The major component of membranes of microbodies from green leaves of Lens culinaris is a protein of a subunit molecular weight of 63 000. This protein, referred to as SP-63, seems to be unique to microbodies and could not be detected when plastids or mitochondria were analyzed. It is probably a structural protein and is thus not solubilized by cholate, Triton X-100, chloroform/methanol, or 0.2M KCl. Solubilization from purified membranes was achieved with guanidinium chloride or sodium dodecylsulphate. The protein was separated from minor contaminating components by chromatography on Sepharose 4B or Sephadex G-150 employing 0.1% sodium dodecylsulphate or 4M urea as eluent. It was shown to be homogeneous upon sodium dodecylsulphate gel electrophoresis and did not give a positive glycoprotein stain.

Guanidines↗
PubMed1976

Plant microbody proteins, III. Labelling of the peroxisomal membrane protein SP-63 in vitro and in vivo.

Methods were developed to charcterize membranes and membrane components of leaf peroxisomes from Lens culinaris. While microbodies from etiolated young leaves exhibited an equilibrium density of 1.19 g/cm3, older leaves or leaves exposed to light for increasing periods of time contained microbodies banding at higher densities up to 1.235 g/cm3. Similar values were also found for the corresponding microbody membranes, which could be labelled with diazotized [35S]sulphanilic acid. Labelling was also performed using proteins extracted from the membranes. Their main structural protein (SP-63) was solubilized with sodium dodecylsulphate and labelled with fluorescent compounds as well as with diazotized [35S]sulphanilic acid or [3H]iodoacetic acid. These conversions greatly facilitate all analytical procedures, e.g. tracing the migration of SP-63 in gels or the movement in sucrose gradients containing sodium dodecylsulphate during zonal centrifugation. Also, labelling of SP-63 in vivo was accomplished when labelled amino acids were infused into etiolated leaves while exposing them to light.

Darkness↗
PubMed1975

The conversion of L-phenylalanine into benzoic acid on the thylakoid membrane of higher plants.

The conversion of L-phenylalanine into benzoic acid and other aromatic carboxylic acids was investigated in Nasturtium officinale (watercress), Astilbe chinensis, and Hydrangea macrophylla in vivo and in vitro. Comparative feeding experiments with radioactively labelled L-phenylalanine and cinnamic acid administered to intact leaf discs of A. chinensis indicated a rapid formation of benzoic acid from L-phenylalanine, whereas cinnamic acid was a poor precursor. Using a pulse-chase labelling technique followed by a fractionation of the tissue into subcellular components, chloroplasts could be identified as the predominant, if not exclusive, site of benzoic acid formation in A. chinensis. Experiments in vitro with chloroplasts and thylalkoids of N. officinale, H. macrophylla, and A. chinensis demonstrate the capacity of thylakoid membranes to catalyze the degradation of L-phenylalanine to benzoic acid. The results obtained upon stimultaneous incubation with [4'-3H]L-phenylalanine and [3-14C]cinnamic acid lead to the hypothesis that the reaction of L-phenylalanine to benzoic acid proceeds via a cinnamic acid pool which is different from that of soluble cinnamic acid.

Benzoates↗