Uptake rate measurement of some amino acids on normal and treated yeast cells to xenobiotics using 14C labelled amino acid.

Abstract:

Benzo(alpha)pyrene (BP) and 7,12--dimethylbenz(alpha) anthracene (DMBA) are potent carcinogens for mammals, which are able to affect the normal metabolic processes. The influence both of BP and DMBA to the transport rate of individual 14C labeled amino acids

(14C-lysine; 14C-valine; 14C-leucine or 14C-tyrosine) in yeast Saccharomyces cerevisiae strain A3 were studied by introducing about one microCi (37 kBq) of individual 14C labeled amino acid into 30 ml liquid ethanol media that contained BP (0.001% v/v) or DMBA (0.001% v/v), then followed by inoculating a known concentration of yeast suspension in such a manner to get the initial optical density (OD) of new cultures were about 0.10. Uptake rates were determined at certain intervals after inoculation, using a liquid scintillation counter. The results show that BP had the tendency to increase the uptake rate while DMBA showed a reversed effect on the use of amino acids. It was also found that tyrosine was absorbed faster than valine as well as leucine and this was different with the result reported by the former investigators.

Nurhajati Tanudjojo, Pringgo Soedigdo, Soekeni Soedigdo

Centre for Research and Development of Nuclear Techniques, National Nuclear Energy Agency, Bandung, Indonesia.