Publications by authors named "M D Leonida"

The present work reports on two approaches to enhance catalase (CAT) activity and its stability by using two simple, green processes. In the first procedure, CAT was transiently exposed to an ionic liquid (IL) in the presence of redox molecules related to CAT structure which resulted in partial denaturation. The other method, which uses high hydraulic pressure (HHP) to partially denature CAT (in the presence of redox molecules), has the advantage of being completely reagentless.

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Matrix metalloproteinases (MMPs) are endopeptidases, and their activity depends on calcium and zinc metal ions. These enzymes are expressed originally in zymogenic form, where the active site of proteins is closed by a prodomain which is removed during activation. A homeostatic balance of their activity is primarily regulated by a 'cysteine switch' located on a consensus sequence of the prodomain and natural endogenous inhibitors, called tissue inhibitors of metalloproteinases (TIMPs).

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Prolonged skin exposure to UV radiation may result in sunburn, with possible inflammatory and oxidative stress to the skin, skin photoaging, photocarcinogenesis, even DNA damage, and apoptosis if sunscreen protection is not used. Due to the advantages that they offer, high encapsulation capability, increased stability of encapsulated bioactive agents, and release control, nanoparticulate materials have been used in sunscreens despite the hazard that they present: their capacity to penetrate the skin causing toxic side effects (especially the chemical sunscreens). The present study reports the preparation of nanoparticulate composites containing only GRAS substances and using an eco-friendly, inexpensive procedure.

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This study investigates the effect of addition of tannic acid on nisin encapsulated in chitosan matrices. Composite materials were prepared using a mild, environmentally friendly procedure, ionotropic gelation of chitosan by sodium tripolyphosphate in the presence of nisin (N) at different concentrations. In two parallel sets of preparations, tannic acid (TA) was added at 10:1 and 5:1 N:TA, respectively.

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The study describes two approaches to enhance oxidoreductases. Both target molecular "wiring" of enzymes using green processes. The concepts were tested on plasma amine oxidase (PAO).

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