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Core-shell polymer particles with different properties were produced through combined suspension-emulsion polymerizations and employed as supports for immobilization of lipase B from Candida antarctica. In order to evaluate how the morphology of the particles affects the immobilization parameters, empirical models were developed to describe the performance of the biocatalysts as a function of the specific area, volume of pores and average pore diameter of the supports. It was observed that the average pore sizes did not affect the enzymatic activities in the analyzed range of pore sizes. It was also observed that the increase of the specific area (and of the volume of pores) led to higher enzyme loadings, also leading to an increase in the esterification activity, as expected. However, when the specific area (and volume of pores) increased, the hydrolytic activity and the retention of hydrolytic activity of the biocatalysts decreased, indicating the existence of diffusional limitations for some hydrolytic reactions, probably because of the high reaction rates.

Soc. Bras. Química 0103 -5053 $6.00+0.00 trypanocidal activity in compounds with an imidazole or oxazole ring linked to a naphthopyrane structure. Two naphthoimidazoles presented higher activities (14.5x and 34.8x) than the standard crystal violet. Emphasis is given to the biodiversity of the Brazilian flora as a starting point for the development of an autonomous and creative medicinal chemistry.

Antimalarial Activity of Phenazines from Lapachol, β-Lapachone and Its Derivatives Against Plasmodium falciparum in vitro and Plasmodium berghei in vivo. -The synthesis of some benzophenazines by reaction of naturally occurring naphthoquinones, lapachol (Ia) and β-lapachone (IVa), or their derivatives with phenylenediamine and the evaluation of their antimalarial activities in vitro and in vivo are described. (No yields given.) -(DE ANDRADE-NETO, V. F.; GOULART, M. O. F.; DA SILVA FILHO, J. F.; DA SILVA, M. J.; PINTO, M. D. C. F. R.; PINTO, A. V.; ZALIS, M. G.; CARVALHO, L. H.; KRETTLI*, A. U.; Bioorg. Med.

An intensive effort has been directed toward finding alternative drugs for treatment of Chagas' disease, caused by Trypanosoma cruzi, and prophylaxis of blood in endemic areas. Our research comprises the synthesis and trypanocidal screening of derivatives from naphthoquinones. Herein a new phenazine, obtained from the reaction of beta-lapachone with aniline, has its structure established by physical data and X-ray analysis. It was 9 times more active against T. cruzi trypomastigotes than crystal violet.

This paper shows the production of lipase B from Candida antarctica (LIPB) after cloning the gene that encoded it in Pichia pastoris using PGK as a constitutive promoter. The lipase was immobilized on different home-made supports for distinct reactions.

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