Studies on L-methioninase Formation by Some Yeast Isolates
L-methioninas e / Formation / Yeast
The greater dependency of cancer cells on L-methionine for growth compared to normal cells indicates that depletion of Lmethionine using L-methioninase is effective for cancer therapy. Accordingly, the exploitation of L-methioninase as a promising enzyme for anticancer therapy necessitates the search for new isolates producing L-methioninase. Therefore, the present study focused on screening of different yeast isolates (locally isolated from soil, marine water or some cheese products) for their ability to produce L-methioninase (the subject of this thesis). Optimization of cultural and nutritional conditions required for maximum enzyme formation by the most promising yeast isolate was studied. Moreover, purification and characterization of L-methioninase from CFE of the selected yeast isolate were investigated. In addition, the antitumor activity of the purified enzyme was evaluated. The results obtained in this study could be summarized as follows: 1- Screening studies showed that out of 50 yeast isolates tested, Isolate No.5 was the most promising isolate which showed the highest L-methioninase formation.