An increasingly important consideration when planning the synthesis of biological active organic moleculesis the introduction of chirality. One method to achieve this is to use a chiral catalyst, such as an enzyme,which are highly enantiose/ective and specific, a feature that facilitates the preparation of target chiratpharmacologically active compounds. An additional property that makes these biocatalysts attractive to theorganic chemist, is that their properties, such as enantioselectivity, prochiral selectivity and specificity arecontrolled by organic solvents (when used as the reaction medium). Olso, enzymes are inexpensive, theycan be 'recycled' and are non toxic.Unfortunately there are some drawbacks that limit their applications and potential. The root of the problemis that the mechanism of enzymatic catalysis in non-aqueous media is still not well understood, andconsequently a trial and error approach is usually needed to find the best medium, enzymes and conditions.The goal of this study is to elucidate the mechanism by which organic solvents influence enzymaticstereoselectivity, activity and stability, and thereby enable the rational design of stereoselective systemsusing the physicochemical properties of the substrate and solvents, together with the enzyme structure. Wepropose to use a combination of experimental and theoretical methods (enzyme kinetics, sophisticatedmolecular-modeling and NMR methods) to understand the role of the medium in shaping a biocatalyststructure, activity and stereoselectivity.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Minority Biomedical Research Support - MBRS (S06)
Project #
Application #
Study Section
Minority Programs Review Committee (MPRC)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Puerto Rico at Humacao
United States
Zip Code
Gawronski, Katerina A B; Kim, Junhyong (2017) Single cell transcriptomics of noncoding RNAs and their cell-specificity. Wiley Interdiscip Rev RNA 8:
Falk, Samantha J; Lee, Jaehyoun; Sekulic, Nikolina et al. (2016) CENP-C directs a structural transition of CENP-A nucleosomes mainly through sliding of DNA gyres. Nat Struct Mol Biol 23:204-208
Falk, Samantha J; Guo, Lucie Y; Sekulic, Nikolina et al. (2015) Chromosomes. CENP-C reshapes and stabilizes CENP-A nucleosomes at the centromere. Science 348:699-703
Sanchez-Cruz, Pedro; Santos, Areli; Diaz, Stephany et al. (2014) Metal-independent reduction of hydrogen peroxide by semiquinones. Chem Res Toxicol 27:1380-6
Piñero-Santiago, Luis E; García, Carmelo; Lhiaubet-Vallet, Virginie et al. (2013) Photooxidation mechanism of levomepromazine in different solvents. Photochem Photobiol 89:1479-89
Bryant, Jessica M; Meyer-Ficca, Mirella L; Dang, Vanessa M et al. (2013) Separation of spermatogenic cell types using STA-PUT velocity sedimentation. J Vis Exp :
Castillo, Betzaida; Bromberg, Lev; López, Xaira et al. (2012) Intracellular Delivery of siRNA by Polycationic Superparamagnetic Nanoparticles. J Drug Deliv 2012:218940
Sanchez-Cruz, Pedro; Dejesus-Andino, Francisco; Alegria, Antonio E (2012) Roles of hydrophilicities and hydrophobicities of dye and sacrificial electron donor on the photochemical pathway. J Photochem Photobiol A Chem 236:54-60
Stepanenko, Viatcheslav; de Jesús, Melvin; Garcia, Carmelo et al. (2012) Synthesis and stability of new spiroaminoborate esters. Tetrahedron Lett 53:910-913
Bansal, Vibha; Delgado, Yamixa; Legault, Marc et al. (2012) Low operational stability of enzymes in dry organic solvents: changes in the active site might affect catalysis. Molecules 17:1870-82

Showing the most recent 10 out of 65 publications