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Geranylgeranyl diphosphate (GGPP) synthase was purified to homogeneity from bovine brain in a one-step affinity column procedure. For the construction of the affinity column, a farnesyl diphosphate (FPP) analog, CM6-amino-l-hexyl)-P- -farnesylmethyl phosphonophosphate, was synthesized and linked to the spacer of the matrix of Affigel 10 via the amino group. The native enzyme appeared to be homooligomer (150-195 kDa) with a molecular mass of the monomer of 37.5 kDa. The pi for the enzyme was 6.2. The Km values for dimethylallyl diphosphate (DMAPP), geranyl diphosphate (GPP) and FTP were estimated to be 33 uM, 0.80 uM and 0.74 uM, respectively. The Km value for isopentenyl diphosphate (IPP) in the presence of both IPP and FPP mixture was 2|iM. The ratio of the reaction velocity for formation of GGPP from DMAPP, GPP or FPP was 0.004:0.145:1. The intermediate FPP was formed in the reaction with GPP as an allylic primer. FPP synthase catalyzing the formation of FPP from DMAPP and IPP was also purified to homogeneity from the same organ by a similar affinity chromatography procedure using a GPP analog, 0-(6-amino-l-hexyl)- -P-geranylmethyl phosphonophosphate as a ligand. The enzyme was a homodimer with a monomeric molecular mass of 40.0 kDa. These results indicate that GGPP, a lipid precursor for the biosynthesis of a majority of prenylated proteins, is synthesized from DMAPP and IPP by the action of FPP synthase catalyzing the reactions C5->C15 followed by the action of GGPP synthase catalyzing the reaction C15->C20.
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The distribution and occurrence of polyisoprenoids (dolichols and polyprenols) in the leaves and roots of nine true Okinawan mangroves and the leaves of one associate mangrove were analyzed using two-dimensional thin layer chromatography. In the leaves, the distribution of three types (I, II, and III) of polyprenols and dolichols were detected. (I) The predominance of dolichols over polyprenols (more than 90%) was observed in Avicennia marina, Bruguiera gymnorrhiza, B. gymnorrhiza (yellow leaves), and Rhizophora stylosa. (II) The occurrence of both polyprenols and dolichols is observed in Excoecaria agallocha, Kandelia obovata, K. obovata (yellow leaves), Lumnitzera racemosa, Pemphis acidula, and Sonneratia alba. (III) The predominance of polyprenols over dolichols (more than 90%) is observed in Heritiera littoralis and Hibiscus tiliaceus. However, in the roots, a type-I distribution was observed in A. marina, B. gymnorrhiza, E. agallocha, H. littoralis and S. alba. A type-II distribution was observed in K. obovata, L. racemosa, P. acidula, and R. stylosa with no type-III distribution. The chain-length distribution of dolichols in the leaves and roots was C50–C140 and C60–C120, respectively. A similar chain-length distribution of polyprenols of C45–C140 and C65–C85 was detected in the leaves and roots respectively. Taken together, sixteen out of twenty-one tissues indicated that dolichols are more abundant than polyprenols in both leaves and roots. The present study is the first to clarify the diversity of polyisoprenoids in both the leaves and roots of mangrove, suggesting the chemotaxonomic significance of polyisoprenoids in the mangrove tree species.
Geranylgeranoic acid (GGA) and 2,3-dihydrogeranylgeranoic acid (2,3-diGGA) are geranylgerani-ol-derived metabolites (Kodaira et al.(2002) J Biochem132:327–334). In the present study, we examined the effects of these acids on HL-60 cells. The cells were differentiated into neutrophils by GGA stimulation like retinoic acid stimulation. In the case of cells stimulated with 2,3-diGGA, neutrophils were not detected, but the formation of lipid droplets was induced. On the other hand, when the cells were cultured in the presence of 0.1% FBS instead of 10% FBS, apoptotic cells were induced not only by GGA stimulation but also with 2,3-diGGA. In the latter case, when the cells were cultured in the co-presence of a caspase-3 inhibitor (Ac-DMQD-CHO), the lipid droplets formation was observed in the cells. These results suggest that GGA and 2,3-diGGA are extremely different from each other with respect to their effects on HL-60 cells.
Dolichols isolated from leaves of the fern Matteucia struthiopteris were present as a mixture of prenologues composed of 14 up to 20 isoprene units with Dol-16 dominating. They comprised approximately 0.004% of the fresh weight of fresh plant tissue and were accompanied by traces of polyprenols (Pren-14 up to Pren-17, Pren-16 dominating). Their structure was confirmed by electropray ionization mass spectrometry (ESI-MS). This is the first time that dolichols have been reported as dominating polyisoprenoid alcohols in plant photosynthetic tissue.
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