Isoprenoid Side Chain Research Articles

Inhibition of vertebrate squalene epoxidase by isoprenyl gallates and phenylalkyl gallates

Galloy esters with ‘substrate-like’ isoprenoid or phenylalkyl side chains were newly synthesized and tested for the enzyme inhibition activities toward recombinant rat squalene epoxidase. Isoprenyl gallates ( 4– 6 ) showed good inhibition (IC 50=1.5–5.1 μM), as potent as previously reported substrate analogues, while phenylalkyl gallates ( 7– 10 ) were moderate inhibitors of the enzyme (IC 50=12–61 μM).

Three Classes of Ubiquinone Analogs Regulate the Mitochondrial Permeability Transition Pore through a Common Site

To identify the structural features required for regulation of the mitochondrial permeability transition pore (PTP) by ubiquinone analogs (Fontaine, E., Ichas, F., and Bernardi, P. (1998) J. Biol. Chem. 40, 25734-25740), we have carried out an analysis with quinone structural variants. We show that three functional classes can be defined: (i) PTP inhibitors (ubiquinone 0, decylubiquinone, ubiquinone 10, 2,3-dimethyl-6-decyl-1,4-benzoquinone, and 2,3,5-trimethyl-6-geranyl-1,4-benzoquinone); (ii) PTP inducers (2,3-dimethoxy-5-methyl-6-(10-hydroxydecyl)-1,4-benzoquinone and 2,5-dihydroxy-6-undecyl-1,4-benzoquinone); and (iii) PTP-inactive quinones that counteract the effects of both inhibitors and inducers (ubiquinone 5 and 2,3,5-trimethyl-6-(3-hydroxyisoamyl)-1,4-benzoquinone) . The structure-function correlation indicates that minor modifications in the isoprenoid side chain can turn an inhibitor into an activator, and that the methoxy groups are not essential for the effects of quinones on the PTP. Since the ubiquinone analogs used in this study have a similar midpoint potential and decrease mitochondrial production of reactive oxygen species to the same extent, these results support the hypothesis that quinones modulate the PTP through a common binding site rather than through oxidation-reduction reactions. Occupancy of this site can modulate the PTP open-closed transitions, possibly through secondary changes of the PTP Ca(2+) binding affinity.

Structure of the F420H2:quinone oxidoreductase of Archaeoglobus fulgidus identification and overproduction of the F420H2-oxidizing subunit.

The F420H2:quinone oxidoreductase from the sulfate-reducing archaeon Archaeoglobus fulgidus is encoded by the fqo gene cluster which comprises 11 genes (fqo J, K, M, L, N, A, BC, D, H, I, F). The last gene of the cluster, fqoF, was overexpressed in Escherichia coli. The purified subunit was able to oxidize reduced cofactor F420 using the electron-acceptor system methyl viologen plus metronidazole. The specific activity at 78 degrees C was 64 micromol F420H2 oxidized. min-1.(mg protein)-1. The purified polypeptide contained 10.6 mol non-heme iron, 7.2 mol acid-labile sulfur and 0.7 mol FAD per mol protein. With the exception of fqoF, the deduced amino-acid sequences of all other genes show homologies to distinct subunits of NADH-quinone oxidoreductases from prokaryotes and eukaryotes. Thus, it is concluded that the F420H2-dependent and the NADH-dependent enzyme are functional equivalents. Both proteins are the initial enzymes of membrane-bound electron-transport systems and are involved in energy conservation. In parallel with bacterial complex I, the F420H2:quinone oxidoreductase may be composed of three subcomplexes. FqoF functions as the input device adjusted to the oxidation of reduced cofactor F420H2, thereby replacing subunits of the input module of complex I that are not present in A. fulgidus. The subunits FqoB, FqoCD and FqoI may form the membrane-associated module and transfer electrons to the membrane-integral module. It is most likely that the last subcomplex is composed of FqoA, FqoH, FqoJ, FqoK, FqoL, FqoM and FqoN. All subunits are highly hydrophobic and are probably involved in the reduction of a special menaquinone with a fully reduced isoprenoid side chain present in the cytoplasmic membrane of A. fulgidus.

Ubiquinone. Biosynthesis of quinone ring and its isoprenoid side chain. Intracellular localization.

Ubiquinone, known as coenzyme Q, was shown to be the part of the metabolic pathways by Crane et al. in 1957. Its function as a component of the mitochondrial respiratory chain is well established. However, ubiquinone has recently attracted increasing attention with regard to its function, in the reduced form, as an antioxidant. In ubiquinone synthesis the para-hydroxybenzoate ring (which is the derivative of tyrosine or phenylalanine) is condensed with a hydrophobic polyisoprenoid side chain, whose length varies from 6 to 10 isoprene units depending on the organism. para-Hydroxybenzoate (PHB) polyprenyltransferase that catalyzes the condensation of PHB with polyprenyl diphosphate has a broad substrate specificity. Most of the genes encoding (all-E)-prenyltransferases which synthesize polyisoprenoid chains, have been cloned. Their structure is either homo- or heterodimeric. Genes that encode prenyltransferases catalysing the transfer of the isoprenoid chain to para-hydroxybenzoate were also cloned in bacteria and yeast. To form ubiquinone, prenylated PHB undergoes several modifications such as hydroxylations, O-methylations, methylations and decarboxylation. In eukaryotes ubiquinones were found in the inner mitochondrial membrane and in other membranes such as the endoplasmic reticulum, Golgi vesicles, lysosomes and peroxisomes. Still, the subcellular site of their biosynthesis remains unclear. Considering the diversity of functions of ubiquinones, and their multistep biosynthesis, identification of factors regulating their cellular level remains an elusive task.

Timing of early diagenetic sulfurization of organic matter: a precursor-product relationship in Holocene sediments of the anoxic Cariaco Basin, Venezuela

The incorporation of reduced inorganic sulfur into organic matter is a significant mechanism for the preservation of functionalized organic compounds in the sedimentary environment, but the timing of this process is not currently known. Analysis of organic matter in the Holocene and latest Pleistocene sediments of the Cariaco Basin indicates conversion of a triunsaturated tricyclic triterpenoid, (17E)-13β(H)-malabarica-14(27),17,21-triene, identified by isolation and subsequent one- and two-dimensional 1H and 13C NMR spectroscopy, to a monounsaturated triterpenoid thiane through incorporation of reduced inorganic sulfur species into the isoprenoid side chain within the upper 6 m of sediments. Time control provided by AMS 14C dates was used in conjunction with measured relative abundances of the two compounds to calculate the reaction rate for the sulfurization of this triterpenoid, and empirically determine the first order rate constant (2 × 10 −4 yr −1) for the reaction. This is the first time that such a precursor-product relationship has been positively identified for a sulfurization reaction in sediments.

Geranylhydroquinone 3"-hydroxylase, a cytochrome P-450 monooxygenase from Lithospermum erythrorhizon cell suspension cultures.

Geranylhydroquinone 3"-hydroxylase, which is likely to be involved in shikonin and dihydroechinofuran biosynthesis, was identified in cell suspension cultures of Lithospermum erythrorhizon Sieb. et Zucc. (Boraginaceae). The enzyme hydroxylates the isoprenoid side chain of geranylhydroquinone (GHQ), a known precursor of shikonin. Proton/proton correlation spectroscopic and proton/proton long-range correlation spectroscopic studies confirmed that hydroxylation takes place specifically at position 3", i.e. at the methyl group involved in the cyclization reaction. The enzyme is membrane-bound and was found in the microsomal fraction. It requires NADPH and molecular oxygen as cofactors, and is inhibited by cytochrome P-450 inhibitors such as cytochrome c and CO. The inhibitory effect of CO is reversed by illumination. These data suggest that the enzyme is a cytochrome P-450-dependent monooxygenase. The optimum pH of GHQ 3"-hydroxylase is 7.4, and the apparent K(m) value for GHQ is 1.5 microM. The reaction velocity obtained with 3-geranyl-4-hydroxybenzoic acid was more than 100 times lower than that obtained with geranylhydroquinone.

Synthesis of [ 11C] coenzyme Q-related compounds for in vivo estimation of mitochondrial electron transduction and redox state in brain

We have studied the synthesis of [ 11C]2,3-dimethoxy-5-methyl-6-(10-hydroxy)-decyl-1,4-benzoquinone (idebenone) and [ 11C]2,3-dimethoxy-5-methyl-1,4-benzoquinone (CoQ 0) by methylation of their respective desmethyl precursors using [ 11C]CH 3I for in vivo measurement of mitochondrial electron transfer and redox state. The [ 11C]idebenone was more lipophilic than [ 11C]CoQ 0; the latter became hydrophilic by reduction. Clearance of [ 11C]idebenone from mouse brain was more rapid than that of [ 11C]CoQ 0. The results indicated that modification of the isoprenoid side chain in [ 11C]CoQ is necessary to develop more suitable radiopharmaceuticals.

29] Determination of vitamin E forms in tissues and diets by high-performance liquid chromatography using normal-phase diol column

Publisher Summary This chapter discusses the determination of various forms of vitamin E in tissues and diets by high-performance liquid chromatography (HPLC) using normal-phase diol column. Vitamin E is a generic term that includes a mixture of tocopherols (T) and tocotrienols (T 3 ) that differs in the number and position of methyl groups on the fused chromanol ring and the absence or presence of three double bonds in the isoprenoid side chain. The present method for the determination of all the vitamin E forms in tissues eliminates the thawing step by pulverizing the tissue at dry ice temperature. Total vitamin E is extracted with hexane and analyzed directly by HPLC using diol column and fluorescence detection, without prior saponification of the sample. The method is modified for the analysis of diets to determine both free and esterified vitamin E. The chapter discusses the response factors of the different forms of vitamin E, the use of internal standards to quantitate vitamin E, and the structure and properties of the diol column. The diol column appears to combine the superior separation of normal-phase silica columns with the added stability and reproducibility that the epoxide structure of the packing material provides. The chapter concludes with a discussion of the influence of triacylglycerols on the quantitation of vitamin E using fluorescence detection.

The gerC locus of Bacillus subtilis, required for menaquinone biosynthesis, is concerned only indirectly with spore germination.

The gerC region of Bacillus subtilis comprises a tricistronic operon, encoding enzymes that catalyse the late stages of menaquinone biosynthesis. The gerC58 mutation is responsible for a severe growth defect; unsuppressed mutant cells grow as very short rods, which sometimes septate aberrantly. Cultures grow only to a low cell density, rapidly lose viability, and never sporulate. Unlinked suppressor mutations can restore near-normal growth. Several independent suppressed isolates were examined; all grew to normal cell length, but they showed, to varying extents, a residual defect in the placement of the cell division septum. The germination properties of the suppressed derivatives varied from normal to significantly slow in germination in all germinants; therefore, the combination of the gerC mutation and different suppressor alleles resulted in spores with very different germination properties. This suggests that any relationship between the gerC gene products and spore germination is indirect. The gerCC58 mutation maps in a gene encoding the catalytic subunit of the heptaprenyldiphosphate synthase, which is responsible for formation of the isoprenoid side chain of menaquinone-7, and it is proposed that the gerCA, gerCB and gerCC genes be renamed hepA, menG and hepB, respectively.

Studies on the Biosynthesis of Terpenoid Compounds Produced by Actinomycetes. 3. Biosynthesis of the Isoprenoid Side Chain of Novobiocin via the Non-mevalonate Pathway in Streptomyces niveus.

Studies on the Biosynthesis of Terpenoid Compounds Produced by Actinomycetes. 3. Biosynthesis of the Isoprenoid Side Chain of Novobiocin via the Non-mevalonate Pathway in Streptomyces niveus.

Incorporation of 2-C-Methyl-d-erythritol, a Putative Isoprenoid Precursor in the Mevalonate-Independent Pathway, into Ubiquinone and Menaquinone of Escherichia coli

Incorporation of deuterium labelled 2-C-methyl-d-erythritol into isoprenoid side-chains of ubiquinone and menaquinone from Escherichia coli strongly supports the proposed intermediate role of this branched sugar derivative in the mevalonate independent pathway for isoprenoid biosynthesis via glyceraldehyde 3-phosphate and pyruvate. © 1997 Published by Elsevier Science Ltd.

Inhibition of Proliferation of Estrogen Receptor–Negative MDA-MB-435 and –Positive MCF-7 Human Breast Cancer Cells by Palm Oil Tocotrienols and Tamoxifen, Alone and in Combination

Tocotrienols are a form of vitamin E, having an unsaturated isoprenoid side-chain rather than the saturated side-chain of tocopherols. The tocotrienol-rich fraction (TRF) from palm oil contains alpha-tocopherol and a mixture of alpha-, gamma- and delta-tocotrienols. Earlier studies have shown that tocotrienols display anticancer activity. We previously reported that TRF, alpha-, gamma- and delta-tocotrienols inhibited proliferation of estrogen receptor-negative MDA-MB-435 human breast cancer cells with 50% inhibitory concentrations (IC50) of 180, 90, 30 and 90 microg/mL, respectively, whereas alpha-tocopherol had no effect at concentrations up to 500 microg/mL. Further experiments with estrogen receptor-positive MCF-7 cells showed that tocotrienols also inhibited their proliferation, as measured by [3H] thymidine incorporation. The IC50s for TRF, alpha-tocopherol, alpha-, gamma- and delta-tocotrienols were 4, 125, 6, 2 and 2 microg/mL, respectively. Tamoxifen, a widely used synthetic antiestrogen inhibits the growth of MCF-7 cells with an IC50 of 0.04 microg/mL. We tested 1:1 combinations of TRF, alpha-tocopherol and the individual tocotrienols with tamoxifen in both cell lines. In the MDA-MB-435 cells, all of the combinations were found to be synergistic. In the MCF-7 cells, only 1:1 combinations of gamma- or delta-tocotrienol with tamoxifen showed a synergistic inhibitory effect on the proliferative rate and growth of the cells. The inhibition by tocotrienols was not overcome by addition of excess estradiol to the medium. These results suggest that tocotrienols are effective inhibitors of both estrogen receptor-negative and -positive cells and that combinations with tamoxifen should be considered as a possible improvement in breast cancer therapy.

Probing Substrate Binding Site of the Escherichia coli Quinol Oxidases Using Synthetic Ubiquinol Analogues

Substrate binding sites of the Escherichia coli bo- and bd-type quinol oxidases were probed with systematically synthesized ubiquinol analogues. The apparent Km values of ubiquinol-2 derivatives to the bo-type enzyme were much lower than that of the corresponding 6-n-decyl derivatives. The isoprenoid structure is less hydrophobic than the saturated n-alkyl group with the same carbon number; therefore, the native isoprenoid side chain appears to play a specific role in quinol binding besides simply increasing hydrophobicity of the molecule. The Vmax values of 2-methoxy-3-ethoxy analogues were greater than that of 2-ethoxy-3-methoxy analogues irrespective of the side chain structure. This result indicates not only that a methoxy group in the 2-position is recognized more strictly than the 3-position by the binding site but also that the side chain structure does not affect binding of the quinol ring moiety. Systematic analysis of the electron-donating activities of the analogues with different substituents in the 5-position revealed that the 5-methyl group is important for the activity. In the parallel studies with the bd-type enzyme, we obtained similar observations except that almost all quinol analogues, but not ubiquinol-1, elicited a remarkable substrate inhibition at higher concentrations. These results indicate that the two structurally unrelated terminal oxidases share common structural properties for the quinol-oxidation site.

Polyprenyl diphosphate synthase essentially defines the length of the side chain of ubiquinone.

Ubiquinone, known as a component of the electron transfer system in many organisms, has a different length of the isoprenoid side chain depending on the species, e.g., Escherichia coli, Saccharomyces cerevisiae and humans have 8, 6, and 10 isoprene units in the side chain, respectively. No direct evidence has yet shown what factors define the length of the side chain of ubiquinone. Here we proved that the polyprenyl diphosphate that was available in cells determined the length of the side chain of ubiquinone. E. coli octaprenyl diphosphate synthase (IspB) was expressed with the mitochondrial import signal in S. cerevisiae. Such cells produced ubiquinone-8 in addition to the originally existing ubiquinone-6. When IspB was expressed in a S. cerevisiae COQ1 defective strain. IspB complemented the defect of the growth on the non-fermentable carbon source. Those cells had the activity of octaprenyl diphosphate synthase and produced only ubiquinone-8. These results opened the possibility of producing the type of ubiquinone that we need in S. cerevisiae simply by expressing the corresponding polyprenyl diphosphate synthase.

Chemistry, Nutritional Sources, Tissue Distribution and Metabolism of Vitamin K with Special Reference to Bone Health

Vitamin K occurs in anture as a series of compounds with a common 2-methyl-1,4 naphthoquinone nucleus and differing isoprenoid side chains at the 3 position. They comprise a single major plant form, phylloquinone with a phytyl side chain and a family of bacterially synthesized menaquinones (MKs) with multiprenyl side chains.The major dietary source to humans is phylloquinone for which the chief food contributors are green, leafy vegetables followed by certain vegetable oils (soybean, rapeseed and olive oils). Recent analyses by high pressure liquid chromatography are now providing a wide-ranging database of phylloquinone in foods. Menaquinones are found in moderate concentrations in only a few foods such as cheeses (MK-8 and MK-9). A wider spectrum of MKs is synthesized by the gut microflora, and their intestinal absorption probably accounts for most of the hepatic stores, particularly those with very long side chains (MKs-10–13) synthesized by members of the genus Bacteroides. The site of absorption of floral MKs is not known, but reasonable concentrations are found in the terminal ileum where bile salt-mediated absorption is possible.Both phylloquinone and menaquinones are bioactive in hepatic gamma-carboxylation but long-chain MKs are less well absorbed. Liver stores of vitamin K are relatively small and predominantly MKs-7–13. The hepatic reserves of phylloquinone (∼10% of the total) are labile and turn over at a faster rate than menaquinones. Trabecular and cortical bone appear to contain substantial concentrations of both phylloquinone and menaquinones. A majority (∼60–70%) of the daily dietary intake of phylloquinone is lost to the body by excretion, which emphasizes the need for a continuous dietary supply to maintain tissue reserves.

A Phospholipid-Dependent NADH-Coenzyme Q Reductase from Liver Plasma Membrane

A 34 kDa coenzyme Q reductase has been solubilized and purified from pig liver plasma membranes. The solubilized enzyme reduced coenzyme Q 0 with NADH. Ubiquinones with longer isoprenoid side chain such as Q 2 and Q 10 were also reduced when the quinones and the enzyme were reconstituted into phospholipid liposomes. N-terminal sequencing of an internal peptide showed identity to bovine NADH-cytochrome b 5 reductase. Biochemical characterization of the purified enzyme indicated that the coenzyme Q reductase corresponds to an unusual form of NADH-cytochrome b 5 reductase.

Erratum: Semiempirical quantum chemical treatment of the standard reduction potentials of quinone and plastoquinone in water

The standard electrode potential for the quinone (Q)-hydroquinone (QH2) couple in aqueous acidic media has been explicitly calculated. Molecular geometries of Q and QH2 have been optimized. Protonation of Q, i.e., the formation of QH+ and QH, have been considered. Molecular geometries of these species have been thoroughly optimized. The energy of complexation of these molecules with water have been calculated by optimizing the structures of the hydrated complexes Q · 6H2O, QH2 · 6H2O, QH+ · 6H2O. and QH · 6H2O. The ion–solvent interaction energy of QH+ · 6H2O, in turn, has been calculated by considering the complex QH+ · 6H2O… 2H2O, where the two extra water molecules approach the charge center of the complex QH+ · 6H2O vertically from top and bottom of the quinonoid ring. The standard reduction potential calculated by the CNDO method, 0.8548 V, is somewhat larger than the experimental potential, 0.6998 V, at 25°C. But the INDO value, 0.7085 V, is in excellent agreement with the observed potential. The electrode potential for the plastoquinone (PQ)-plastohydroquinone (PQH2) couple present in the aqueous pool in chloroplast has been calculated by the INDO method. The basic geometries of PQ, PQH+, and PQH2/sb have been synthesized by adopting the optimized geometries of Q, QH+, and QH2 and considering methyl substituents as well as an isoprenoid side chain containing up to 3 isoprene units with possible geometrical isomerism. The hydrated species PQ · 6H2O, PQH+ · 6H2O, and PQH2 · 6H2O are unstable compared to the isolated species PQ, PQH+, and PQH2, respectively. In fact, we have found that the hydration of PQH+ and PQH2 is much less extensive, and stability arises only when the hydroxyl groups in these two molecules are hydrogen-bonded to water molecules. But PQH+ is also stabilized through the association of two more water molecules in the vertical direction. For this reason, we have calculated the reduction potential of the PQ/PQH2 system from the energies of the isolated molecules PQH2 and the hydrated species PQH+ · 2H2O. The computed standard reduction potential is 0.2785 V and it yields a potential of 0.07V at pH 7 at 25°C, which is in good agreement with the reduction potential 0.11 V observed for plastoquinone in the aqueous pool in chloroplast. © 1994 John Wiley & Sons, Inc.

Semiempirical quantum chemical treatment of the standard reduction potentials of quinone and plastoquinone in water

AbstractThe standard electrode potential for the quinone (Q)‐hydroquinone (QH2) couple in aqueous acidic media has been explicitly calculated. Molecular geometries of Q and QH2 have been optimized. Protonation of Q, i.e., the formation of QH+ and QH, have been considered. Molecular geometries of these species have been thoroughly optimized. The energy of complexation of these molecules with water have been calculated by optimizing the structures of the hydrated complexes Q · 6H2O, QH2 · 6H2O, QH+ · 6H2O. and QH · 6H2O. The ion–solvent interaction energy of QH+ · 6H2O, in turn, has been calculated by considering the complex QH+ · 6H2O…︁ 2H2O, where the two extra water molecules approach the charge center of the complex QH+ · 6H2O vertically from top and bottom of the quinonoid ring. The standard reduction potential calculated by the CNDO method, 0.8548 V, is somewhat larger than the experimental potential, 0.6998 V, at 25°C. But the INDO value, 0.7085 V, is in excellent agreement with the observed potential. The electrode potential for the plastoquinone (PQ)‐plastohydroquinone (PQH2) couple present in the aqueous pool in chloroplast has been calculated by the INDO method. The basic geometries of PQ, PQH+, and PQH2/sb have been synthesized by adopting the optimized geometries of Q, QH+, and QH2 and considering methyl substituents as well as an isoprenoid side chain containing up to 3 isoprene units with possible geometrical isomerism. The hydrated species PQ · 6H2O, PQH+ · 6H2O, and PQH2 · 6H2O are unstable compared to the isolated species PQ, PQH+, and PQH2, respectively. In fact, we have found that the hydration of PQH+ and PQH2 is much less extensive, and stability arises only when the hydroxyl groups in these two molecules are hydrogen‐bonded to water molecules. But PQH+ is also stabilized through the association of two more water molecules in the vertical direction. For this reason, we have calculated the reduction potential of the PQ/PQH2 system from the energies of the isolated molecules PQH2 and the hydrated species PQH+ · 2H2O. The computed standard reduction potential is 0.2785 V and it yields a potential of 0.07V at pH 7 at 25°C, which is in good agreement with the reduction potential 0.11 V observed for plastoquinone in the aqueous pool in chloroplast. © 1994 John Wiley & Sons, Inc.

Cytokinin oxidase: Biochemical features and physiological significance

The catabolism of cytokinin in plant tissues appears to be due, in large part, to the activity of a specific enzyme, cytokinin oxidase. This enzyme catalyses the oxidation of cytokinin substrates bearing unsaturated isoprenoid side chains, using molecular oxygen as the oxidant. In general, substrate specificity is highly conserved and cytokinin substrates bearing saturated or cyclic side chains do not serve as substrates for most cytokinin oxidases tested to date. Despite variation in molecular properties of the enzyme from a number of higher plants, oxygen is always required for the reaction. Cytokinin oxidases from several sources have been shown to be glycosylated. Cytokinin oxidase activity appears to be universally inhibited by cytokinin‐active urea derivatives. Auxin has been reported to act as an allosteric regulator which increases activity of the enzyme.Cytokinin oxidase activity is subject to tight regulation. Levels of the enzyme are controlled by a mechanism sensitive to cytokinin supply. The up‐regulation of cytokinin oxidase expression in response to exogenous application of cytokinin suggests that the metabolic fate of exogenously applied cytokinins may not accurately mimic that of the endogenous compounds.Cytokinin oxidase is believed to be a copper‐containing amine oxidase (EC 1.4.3.6). Considerable evidence strongly supports a common mechanism for amine oxidases. It is possible that advances in understanding of other amine oxidases could be extrapolated to increase our understanding of cytokinin oxidase at the molecular level. This is discussed with reference to what is currently known about the catalytic mechanism of the enzyme. The possibility of pyrroloquinoline quinone, or a closely related compound, as a redox cofactor of cytokinin oxidase is considered, as are the implications of the glycosylated nature of the enzyme for its regulation and compartmentalisation within the cell.

5210077 Antibodies to cytokinins having a glycosylated isoprenoid side chain and immunoassay methods: David L Brandon, Joseph W Corse assigned to The United States of America as represented by the Secretary of Agriculture

5210077 Antibodies to cytokinins having a glycosylated isoprenoid side chain and immunoassay methods: David L Brandon, Joseph W Corse assigned to The United States of America as represented by the Secretary of Agriculture