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Stability of Enzymes and Proteins in Dried Glassy Systems: Effect of Simulated Sunlight Conditions
Author(s) -
Espinosa Luis,
Schebor Carolina,
Nudelman Norma S.,
Chirife Jorge
Publication year - 2004
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp034368m
Subject(s) - chemistry , denaturation (fissile materials) , raffinose , invertase , lysozyme , enzyme , trehalose , chromatography , amylase , anhydrous , mannitol , turbidimetry , enzyme assay , maltodextrin , biochemistry , sucrose , nuclear chemistry , organic chemistry , spray drying
The purpose of the present work was to study the effects of simulated sunlight conditions on enzyme inactivation and structural damage in dehydrated glassy systems. Freeze‐dried samples containing different enzymes (lactase, invertase, lysozyme and amyloglucosidase) were exposed to light using a medium‐pressure metal halide HPA 400 W lamp. After 1 h of light exposure, the samples showed a significant reduction (more than 50%) in the denaturation peak area as analyzed by DSC, and this could be attributed to protein denaturation. For most of the pure enzymes, the loss of enzymic activity after 1 h of light exposure was around 50%. In the case of enzymes included in anhydrous model systems (trehalose, raffinose, maltodextrin, and dextran), the remaining activity also decreased dramatically during the light treatment. We showed that the light exposure in dehydrated systems generated both the loss of enzymic activity and structural changes such as denaturation (observed by DSC) and protein fragmentation and aggregation (observed by electrophoresis). Overall, we can conclude that a short exposure to the light produces dramatic changes in the enzymic activity in dehydrated systems with or without protective matrices.