Proline-fueled mitochondrial metabolism involves the oxidative conversion of L-Proline to LGlutamate in two enzymatic steps by means of Put1p and Put2p that help Saccharomyces cerevisiae to respond to changes in the nutritional environment by initiating the breakdown of L-Proline as a source for nitrogen, carbon, and energy. Compartmentalization of L-Proline catabolic pathway implies that extensive intracellular L-Proline transport must occur between the cytosol, where its biogenesis via Pro1p, Pro2p, Pro3p occurs and mitochondria. L-Proline uptake in Saccharomyces cerevisiae mitochondria was investigated by swelling experiments, oxygen uptake and fluorimetric measurement of a membrane potential generation. Our results strongly suggest that L-Proline uptake takes place via a carried-mediated process as demonstrated by the occurrence of both saturation kinetics and by experiments with Nethylmaleimide, a pharmacological compound that is a cysteine-modifying reagent in hydrophobic protein domains and that inhibited mitochondrial transport. Thus L-Proline®LGlutamate route feeds Krebs cycle providing energy and anaplerotic carbon for yeast survival.

New insights into L-Proline uptake and mitochondrial energetic metabolism in Saccharomyces cerevisiae

PALLOTTA, Maria Luigia
2013

Abstract

Proline-fueled mitochondrial metabolism involves the oxidative conversion of L-Proline to LGlutamate in two enzymatic steps by means of Put1p and Put2p that help Saccharomyces cerevisiae to respond to changes in the nutritional environment by initiating the breakdown of L-Proline as a source for nitrogen, carbon, and energy. Compartmentalization of L-Proline catabolic pathway implies that extensive intracellular L-Proline transport must occur between the cytosol, where its biogenesis via Pro1p, Pro2p, Pro3p occurs and mitochondria. L-Proline uptake in Saccharomyces cerevisiae mitochondria was investigated by swelling experiments, oxygen uptake and fluorimetric measurement of a membrane potential generation. Our results strongly suggest that L-Proline uptake takes place via a carried-mediated process as demonstrated by the occurrence of both saturation kinetics and by experiments with Nethylmaleimide, a pharmacological compound that is a cysteine-modifying reagent in hydrophobic protein domains and that inhibited mitochondrial transport. Thus L-Proline®LGlutamate route feeds Krebs cycle providing energy and anaplerotic carbon for yeast survival.
ISSN 0749-503X
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11695/14278
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