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H Kleinig

Publications and source records attributed to H Kleinig.

At least 37 records · Page 2Linked to original sources
PubMed1984

Synthesis of prenyl lipids in cells of spinach leaf. Compartmentation of enzymes for formation of isopentenyl diphosphate.

Purified spinach chloroplasts incorporate [1-14C]isopentenyl diphosphate into prenyl lipids in high yields. The immediate biosynthetic precursors of isopentenyl diphosphate (hydroxymethylglutaryl-CoA, mevalonate, mevalonate-5-phosphate, mevalonate-5-diphosphate), on the other hand, are not accepted as substrates and the corresponding enzymes hydroxymethylglutaryl-CoA reductase, mevalonate kinase, phosphomevalonate kinase, and diphosphomevalonate decarboxylase are not present in the organelles. These enzymes can only be detected in a membrane-bound form at the endoplasmic reticulum (hydroxymethylglutaryl-CoA reductase) and as soluble activities in the cytoplasm. The concept is developed that isopentenyl diphosphate is formed in the cytoplasm as a 'central intermediate' and is distributed then to other cellular compartments (endoplasmic reticulum, plastids, mitochondria) for further biosynthetic utilization.

Cell Compartmentation↗
PubMed1984

On the biosynthesis of ubiquinones in plant mitochondria.

Isolated mitochondria from potato tubers, spinach leaves, and daffodil petals from intermediates of the ubiquinone biosynthetic pathway (prenylated 4-hydroxybenzoate, prenylated phenols, and quinoid compounds) from [1-14C]isopentenyl diphosphate and endogenous or exogenous 4-hydroxybenzoate. In contrast [2-14C]mevalonate 5-diphosphate, the immediate precursor of isopentenyl diphosphate was not accepted as a substrate. These results suggest that plant mitochondria have their own prenyltransferase and prenylation system, similar to the plastid compartment which also starts by the use of isopentenyl diphosphate [see Kreuz, K. and Kleinig, H. (1984) Eur. J. Biochem. 141, 531-535].

Cell Fractionation↗
PubMed1979

The spherule wall of Physarum polycephalum: chemical analysis and electron microscopy.

1. The composition of purified wall fragments from the spherule wall of Physarum polycephalum has been studied. 2. Spherule wall fragments consist of two major components. More than one-half of the wall material is glycoproteins. The remaining wall material after fractionation has a high carbohydrate to protein ratio and is suggested to be composed of proteoglycan(s). 3. The predominant monosaccharide constituent of the proteoglycan is galactosamine. The protein component is unique. It is composed almost entirely of phenylalanine (87--92 mol%). 4. Approx. 50% of these proteoglycans are resistant to alkali extraction and in negative stained preparation for the electron microscope consist of short spindle-shaped fibrils which measure 100 nm in length and 8 nm in diameter. These fibrils show a weak but distinct X-ray diffraction pattern.

Cell Wall↗
PubMed1978

Carotenoids of rhizobia. II. The effect of nicotine on the carotenoid pattern of Rhizobium lupini.

With increasing concentrations in the growth medium of the cyclization inhibitors nicotine or 2-(4-chlorophenylthio)-triethylamine hydrochloride (CPTA) the previously identified bicyclic carotenoids of Rhizobium lupini (2,3,2',3'-tetrahydroxy-beta,beta-caroten-4-one and 2,3,2',3'-tetrahydroxy-beta,beta-carotene) were successively replaced by hitherto unknown monocyclic carotenoids. By application of mass and nuclear magnetic resonance spectroscopy 3 carotenoids were identified as 2,3-trans-dihydroxy-beta,psi-caroten-4-one, 2,3-trans-dihydroxy-beta,psi-carotene, and 3-hydroxy-beta,psi-caroten-4-one. A further compound was tentatively established as (2- or 3-)monohydroxy-beta,psi-carotene. It was found that other inhibitors such as diphenylamine or 4-chloro-5-(dimethylamino)-2-alpha,alpha,alpha(trifluoro-m-tolyl)-3-(2H)-pyridazinone (San 6706) did not affect the pigment pattern. The results are discussed in relation to carotenoid biosynthesis in Rhizobium lupini.

Carotenoids↗
PubMed1978

Fatty acid synthesis by isolated chromoplasts from the daffodil. [14C]Acetate incorporation and distribution of labelled acids.

Isolated daffodil (Narcissus pseudonarcissus) chromoplasts showed high rates of [14C]acetate incorporation into lipids. The fatty acids synthesized were predominantly palmitic acid (93%). The radioactivity incorporated was shared mainly between long-chain acyl-CoA (25%), free fatty acids (24%), phosphatidic acid (17%), diacylglycerol (15%), and phosphatidycholine (11%). Galactolipids were not labelled. ATP, NaHCO3, and also the structural integrity of the organelles were essential. Omission of exogenous CoA led to a decreased incorporation (49%); under these conditions the label was distributed mainly between free fatty acids (66%) and diacylglycerol (19%). Addition of lysophosphatidylcholine increased the labelling of phosphatidylcholine, whereas addition of glycerol 1-phosphate increased the labelling of phosphatidic acid and diacylglycerol. Acyl-CoA synthetase and acyl thioesterase (acyl-Coa) activities could be demonstrated. The results are discussed in terms of chromoplasts as non-photosynthetic organelles exhibiting high lipid-synthesizing capabilities.

Acetates↗
PubMed1977

Carotenoid glucosides and menaquinones from the gliding bacterium Herpetosiphon giganteus Hp a2.

The gliding bacterium Herpetosiphon giganteus Hp a2 was shown to contain gamma-carotene, one monoglucosyloxy and two new diglucosyloxy carotenoids with a x-O-acyldiglucosyloxy carotenoid as main component. Flexirubin-like pigments could not be detected in this organism. As in the Myxobacterales and Cytophagales (Kleinig et al., 1974) menaquinones (MK-6 and MK-7) were found to be the only isoprenoid quinones present in Herpetosiphon. The chemosystematic implications of these findings are briefly discussed.

Bacteroidetes↗
PubMed1975

On the utilization in vivo of lycopene and phytoene as precursors for the formation of carotenoid glucoside ester and on the regulation of carotenoid biosynthesis in Myxococcus fulvus.

During th logarithmic phase of growth of the myxobacterium Myxococcus fulvus the specific carotenoid content and the molar ratio of the two main carotenoids keto-torulene (3',4'-didehydro-beta,psi-caroten-4-one, 15%) and myxobacton ester (1'-glucosyloxy-3',4'-didehydro-1',2'-dihydro-beta,psi-caroten-4-one ester, 80%) are highly constant. When the formation of these carotenoids was prevented by an inhibitory block at the level of phytoene desaturation, the normal specific content is rapidly reached after release of this block by a two-three-fold enhanced rate of synthesis. The experimentally accumulated phytoene molecules however, are not used as a precursor pool for the formation of the coloured carotenoids. The absolute amount of phytoene does not decrease, although a considerable molecule exchange between this pool and the pathway occurs. Furthermore, experimentally accumulated lycopene is only converted into myxobacton ester when the carotenogenic pathway is blocked at an earlier step, at the level of phytoene desaturation. Without this blockage the lycopene pool remains unaffected. The results are discussed in terms of arrangement of the carotenogenic enzymes in a sort of assembly line in association with the cytoplasmic membrane. Four sites of control are suggested in this pathway.

Carotenoids↗
PubMed1975

Characterization of two cell-envelope fractions from chemotrophically grown Rhodospirillum rubrum.

Two cell-envelope fractions were isolated from chemotrophically grown cells of Rhodospirillum rubrum. On the basis of electron-microscopic investigations, chemical analysis, distribution of components involved in respiration, and poly-acrylamide gel electrophoresis, the heavy fraction (rho20 = 1.246 g per cm3) was identified as cell-wall, and the light fraction (rho = 1.145 g per cm3) as cyto-plasmic-membrane fragments. Electron micrographs showed cell-wall fragments as open structures while cytoplasmic-membrane preparations were composed of closed membrane vesicles. With respect to the main classes of chemical compounds, cell wall could be distinguished from cytoplasmic membranes by a rather low ratio of phospholipids per protein and a high ratio of carbohydrates per protein. The relative proportion of individual neutral sugars as well as phospholipids (except for lysophosphatidyl ethanolamine) revealed no significant differences between both envelope fractions. Fatty acid analysis demonstrated a higher proportion of saturated fatty acids in cell-wall than in cyto-plasmic-membrane fractions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the fractions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the fractions showed distinct protein compositions. While in cell-wall preparations polypeptides of 43,000 and 14,000 daltons predominated, 56,000- and 52,000-dalton polypeptides were the main protein subunits of cytoplasmic membranes. Cross contaminations of both cell-envelope fractions were defined.

Cell Fractionation↗