Previous studies have already reported a novel feature of isolated Saccharomyces cerevisiae mitochondria (SCM), i.e. the capability to taken up externally added riboflavin and synthesise FAD. This has been assumed to occur via riboflavin kinase and FAD synthetase which catalyse FMN synthesis from riboflavin and ATP and FAD from FMN and ATP, respectively. Moreover SMC can export newly synthesised FMN and FAD in the extramitochondrial phase (Pallotta et al, 1998). In the light of cytosolic riboflavin, FMN and FAD concentrations, as calculated by measuring both spheroplast and mitochondrial content via HPLC, probably mitochondria play a important role in regulating the flavin pool in yeast cell. The homeostasis of riboflavin and its coenzymes may be altered by some factors, such as defective FMN and/or FAD synthesis, increased catabolism and altered mitochondrial metabolism and transport. In this work, SCM capability to metabolise externally added and endogenous FAD and FMN was investigated. Experiments were undertaken both spectroscopically and via HPLC. The existence of two novel mitochondrial enzymes, namely FAD pyrophosphatase (diphosphatase)(EC 3.6.1.18) and FMN phosphohydrolase (EC 3.1.3.2), which catalyse FAD-->FMN and FMN-->riboflavin conversion, respectively, is here shown. Moreover, Saccharomyces cerevisiae strains PSY142 and PSY142 derivative of tetradelete (dld1::LEU2, dld2::kanMX4, dld3::URA3, cyb2::LYS2) and (dld2::kanMX4, dld3::URA3), were used in some experiments References Pallotta ML, Brizio C, Fratianni A, De Virgilio C, Barile M, Passarella S. 1998 Febs Lett. 29; 428(3):245-9. PDF created
Flavin adenine dinucleotide(FAD) and flavin mononucleotide (FMN) metabolism in Saccharomyces cerevisiae mitochondria
PALLOTTA, Maria Luigia
2004-01-01
Abstract
Previous studies have already reported a novel feature of isolated Saccharomyces cerevisiae mitochondria (SCM), i.e. the capability to taken up externally added riboflavin and synthesise FAD. This has been assumed to occur via riboflavin kinase and FAD synthetase which catalyse FMN synthesis from riboflavin and ATP and FAD from FMN and ATP, respectively. Moreover SMC can export newly synthesised FMN and FAD in the extramitochondrial phase (Pallotta et al, 1998). In the light of cytosolic riboflavin, FMN and FAD concentrations, as calculated by measuring both spheroplast and mitochondrial content via HPLC, probably mitochondria play a important role in regulating the flavin pool in yeast cell. The homeostasis of riboflavin and its coenzymes may be altered by some factors, such as defective FMN and/or FAD synthesis, increased catabolism and altered mitochondrial metabolism and transport. In this work, SCM capability to metabolise externally added and endogenous FAD and FMN was investigated. Experiments were undertaken both spectroscopically and via HPLC. The existence of two novel mitochondrial enzymes, namely FAD pyrophosphatase (diphosphatase)(EC 3.6.1.18) and FMN phosphohydrolase (EC 3.1.3.2), which catalyse FAD-->FMN and FMN-->riboflavin conversion, respectively, is here shown. Moreover, Saccharomyces cerevisiae strains PSY142 and PSY142 derivative of tetradelete (dld1::LEU2, dld2::kanMX4, dld3::URA3, cyb2::LYS2) and (dld2::kanMX4, dld3::URA3), were used in some experiments References Pallotta ML, Brizio C, Fratianni A, De Virgilio C, Barile M, Passarella S. 1998 Febs Lett. 29; 428(3):245-9. PDF createdI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
