Influence of methionine on S-adenosyl-L-methionine production by yeasts Saccharomyces cerevisiae and Pichia stipitis

S-adenozil-L-metionin (SAMe), metabolit neophodan za život svake stanice, sudjeluje u tri značajna metabolička puta: transmetilaciji, transsulfuraciji i aminopropilaciji. S obzirom na njegove pozitivne učinke u tretiranju raznih bolesti, SAMe danas ima široku primjenu u medicini. Stanice pojedinih kvasaca nakupljaju velike unutarstanične koncentracije SAMe. U ovom su radu ispitane akumulacije SAMe u kvascima S. cerevisiae TVG 4 i P. stipitis DSM 3652 koji su rasli u glukoznim podlogama bez ili uz dodatak D-, L- ili D,L-metionina. Rezultati pokazuju da P. stipitis proizvodi znatno veće količine SAMe od S. cerevisiae te da je proizvodnja SAMe obrnuto proporcionalna brzini rasta stanice. Sva tri izomera metionina stimuliraju akumulaciju SAMe, ali najveće su koncentracije izmjerene prilikom rasta uz prisutnost L-metionina (18,97 g/100 g s. tv. kod P. stipitis; 0,801 g/100 g s. tv. kod S. cerevisiae). Također je utvrđeno da 1,5 g/L D,L-metionina bolje stimulira akumulaciju SAMe od 0,75 ili 2,25 g/L D,L-metionina u podlozi.S-adenosyl-L-methionine (SAMe), a metabolite essential for the life of every cell, is involved in significant metabolic pathways: transmethylation, transsulfuration and aminopropylation. Given its positive effects in treating various diseases, SAMe has a wide application in medicine. Certain yeasts accumulate high intracellular concentrations of SAMe. In this work, the amounts of accumulated SAMe in yeasts S. cerevisiae TVG 4 and P. stipitis DSM 3652, were determined. Yeasts were cultivated in the glucose medium without or with the addition of D-, L- or D,L-methionine. P. stipitis produced greater amounts of SAMe than S. cerevisiae. Production of SAMe was inversely proportional to the cell growth. All three isomers of methionine stimulate the accumulation of SAMe, but the highest concentrations were obtained with the presence of L-methionine in the medium (18,97 g/100 g dry cells in P. stipitis; 0,801 g/100 g dry cells in S. cerevisiae). It was also found that 1,5 g/L D,L-methionine better stimulates the accumulation of SAMe than the presence of 0,75 or 2,25 g/L D,L-methionine in the medium