Glucose exerts a negative effect over a peroxidase from <Emphasis Type="Italic">Trichosporon asahii</Emphasis>, with carotenoid cleaving activity |
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Authors: | Eduardo Rodríguez-Bustamante Gabriela Maldonado-Robledo Roberto Arreguín-Espinosa Guillermo Mendoza-Hernández Romina Rodríguez-Sanoja Sergio Sánchez |
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Institution: | (1) Departamento de Biología Molecular y Biotecnología del Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, D.F., 04510, Mexico;(2) Departamento de Bioquímica, Instituto de Química, Universidad Nacional Autónoma de México, México, D.F., 04510, Mexico;(3) Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, México, D.F., 04510, Mexico |
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Abstract: | Tobacco aroma compounds were generated via lutein cleavage by the combined action of a yeast and a bacterium identified as
Trichosporon asahii and Paenibacillus amylolyticus, respectively. In this study, an inverse relationship between glucose concentration and the generation of three compounds,
present in the tobacco aroma profile, was observed in mixed cultures. In order to identify the organism sensitive to the sugar
effect, both were grown separately. The presence of glucose suppressed β-ionone production by T. asahii grown with lutein. However, the biotransformation of the ionone into its reduced derivatives (7,8-dihydro-β-ionone and 7,8-dihydro-β-ionol)
by P. amylolyticus was not affected by the sugar . This pointed to the cleavage of lutein, a step within the process necessary for the synthesis
of β-ionone, as the target of the glucose effect. In vitro studies with crude extracts and concentrated cell-free medium derived
from T. asahii cultures showed that the carotenoid breakdown activity was located extracellularly and only detected in supernatants from
yeast cells grown in the absence of the sugar. Rather than an inhibition or a mechanism affecting the enzyme secretion, the
glucose effect on lutein degradation comprised another regulatory level. Further experiments showed that the enzyme responsible
for lutein breakdown and susceptible to the sugar effect exhibited a high degree of identity to fungal peroxidases, studied
as well, for their involvement in carotenoid cleavage. |
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Keywords: | Glucose negative effect Lutein cleavage β -ionone and its reduced derivatives Fungal peroxidases |
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