The polymerization of e-caprolactone, (e-CL) using porcine pancreatic lipase (PPL) as the catalyst was studied. Polymerization reactions (4 days, 65 °C) of e-CL at ~10% (w/v) concentrations in dioxane, toluene, and heptane using butanol as an initiating species (monomer/butanol ratio = 14.7) gave poly(e-caprolactone) (PCL) with Mn values (by GPC) of 313, 753, and 1600, respectively. Monomer conversion to PCL for these polymerizations was 33, 55, and 100%, respectively. Mn measurements of PCL products by NMR end group analyses were slightly lower (by a factor of -0.9) than the values obtained by GPC. Polymerizations conducted in heptane at 37, 45, 55, and 65 °C showed the highest extent of monomer conversion at 65 °C. Therefore, subsequent studies were conducted at 65 °C in heptane. For a polymerization carried out with a 15/1 monomer/butanol ratio and ~0.29 mmol of water, ~70 and ~100% of the monomer had been converted to PCL by reaction times of 24 and 96 h, respectively. Polymer molecular weight increased slowly with conversion, suggesting that this is a chain polymerization with rapid initiation and slow propagation. Increases in the e-CL/butanol ratio from 15/1 up to where no butanol was added showed only a modest increase in product molecular weight from 1600 to 2700. This was explained by the fact that the water present in polymerizations was active in chain initiation. Variation in the monomer/butanol ratio at constant water concentration resulted in PCL chains with 0-0.65 mol fraction of butyl ester and 0.33-0.86 mol fraction of carboxylic acid chain end groups (by NMR analyses). The presence of water concentrations in polymerization reactions above that which is strongly enzyme bound is believed to be an important factor which limited the formation of PCL chains of significantly higher molecular weight.

SYNOPSISPolymers were synthesized from substituted phenolic and aromatic amine compounds with hydrogen peroxide as the source of an oxidizing agent and horseradish peroxidase enzyme as the catalyst. The polymerization reaction was carried out in a monophasic organic solvent with small amounts of water at room temperature. Conditions for the synthesis of polymers with respect to reaction time and yield were studied with a number of monomers at different concentrations and in solvents with different buffers with pH range of 5.0-7.5. Physical and chemical properties of these homo-and copolymers were determined with respect to melting point, solubility, elemental analysis, molecular weight distribution, infrared absorption (including FTIR) , solid-state 13C nuclear magnetic resonance, thermal gravimetric analysis, and differential scanning calorimetry. The enzyme catalyzed reactions produced polymers of molecular weight greater than 400,000 which were further fractionated by differential solubility in solvent mixtures and the molecular weight distribution of the polymer fractions were determined. In general, the polymers synthesized have low solubilities, high melting points, and some degree of branching.

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A fluorescent polymer of 2-naphthol is prepared using the oxidative enzyme horseradish peroxidase encapsulated in the microstructured system of AOT/isooctane reversed micelles. The monomer, being amphiphilic, partitions to the oil−water interface with the hydroxyl moieties directed toward the microaqueous core. The enzyme is encapsulated in the water core. The precipitated polymer of naphthol has the morphology of single and interconnected microspheres and is soluble in a range of polar and nonpolar organic solvents. Poly(2-naphthol) shows a fluorescence characteristic of the naphthol chromophore and an additional well-resolved fluorescence attributed to an extended quinonoid structure attached to the polymer backbone. Further evidence of the quinonoid structure is obtained through UV, IR, and NMR spectroscopy. Characteristics of the synthesis and structure of poly(2-naphthol) are compared with those of a less fluorescent polymer, poly(4-ethylphenol).

SCF complexes are the largest and best studied family of E3 ubiquitin protein ligases that facilitate the ubiquitylation of proteins targeted for degradation. The SCF core components Skp1, Cul1, and Rbx1 serve in multiple SCF complexes involving different substrate-specific F-box proteins that are involved in diverse processes including cell cycle and development. In Arabidopsis, mutations in the F-box gene UNUSUAL FLORAL ORGANS (UFO) result in a number of defects in flower development. However, functions of the core components Cul1 and Rbx1 in flower development are poorly understood. In this study we analyzed floral phenotypes caused by altering function of Cul1 or Rbx1, as well as the effects of mutations in ASK1 and ASK2. Plants homozygous for a point mutation in the AtCUL1 gene showed reduced floral organ number and several defects in each of the four whorls. Similarly, plants with reduced AtRbx1 expression due to RNA interference also exhibited floral morphological defects. In addition, compared to the ask1 mutant, plants homozygous for ask1 and heterozygous for ask2 displayed enhanced reduction of B function, as well as other novel defects of flower development, including carpelloid sepals and an inhibition of petal development. Genetic analyses demonstrate that AGAMOUS (AG) is required for the novel phenotypes observed in the first and second whorls. Furthermore, the genetic interaction between UFO and AtCUL1 supports the idea that UFO regulates multiple aspects of flower development as a part of SCF complexes. These results suggest that SCF complexes regulate several aspects of floral development in Arabidopsis.An Arabidopsis flower has four concentric whorls that contain four sepals, four petals, six stamens, and two carpels. After the transition from vegetative to reproductive development, the Arabidopsis apical meristem (inflorescence meristem) produces the floral meristem, which in turn undergoes a series of developmental stages to form a flower (Smyth et al., 1990). Genetic and molecular studies have uncovered a large number of genes that control different steps in flower development including flowering time, flower meristem identity, and flower organ identity (Zhao et al., 2001a). In particular, the ABC model has been proposed for the specification of floral organ identity (Coen and Meyerowitz, 1991;Ma, 1994;Weigel and Meyerowitz, 1994;Ma and dePamphilis, 2000). The combinatorial expression of ABC genes defines the organ type that differentiates in each whorl: A function alone specifies the sepal identity; A and B function together controls petal identity; B and C function together specifies stamen identity; and C function alone directs carpel identity.The UNUSUAL FLORAL ORGANS (UFO) gene is involved in multiple aspects of floral development, including regulating floral meristem identity and floral organ development (Levin and Meyerowitz, 1995;Wilkinson and Haughn, 1995). One known function of UFO in floral organ development is a positive regulation of the expression of B function gene APETALA3 (A...