Oversynthesis of riboflavin in the yeast Pichia guilliermondii is accompanied by reduced catalase and superoxide dismutases activities.
Iron deficiency causes oversynthesis of riboflavin in several yeast species, known as flavinogenic yeasts. Under iron deprivation conditions, Pichia guilliermondii cells increase production of riboflavin and malondialdehyde and the formation of protein carbonyl groups, which reflect increased intracellular content of reactive oxygen species. In this study, we found that P. guilliermondii iron deprived cells showed dramatically decreased catalase and superoxide dismutase activities. Previously reported mutations rib80, rib81, and hit1, which affect repression of riboflavin synthesis and iron accumulation by iron ions, caused similar drops in activities of the mentioned enzymes. These findings could explain the previously described development of oxidative stress in iron deprived or mutated P. guilliermondii cells that overproduce riboflavin. Similar decrease in superoxide dismutase activities was observed in iron deprived cells in the non-flavinogenic yeast Saccharomyces cerevisiae.
Department of Analytical Biotechnology, Institute of Cell Biology NAS of Ukraine, Lviv, Ukraine.
Tetyana M
TM
Prokopiv
Dariya V
DV
Fedorovych
Yuriy R
YR
Boretsky
Andriy A
AA
Sibirny
D002374:Catalase / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress; D010843:Pichia / Q000201:enzymology* / Q000378:metabolism* / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D012256:Riboflavin / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*
D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D007501:Iron; D002374:Catalase; D013482:Superoxide Dismutase; D012256:Riboflavin