title: [Role of cytochrome P-450 in strain D7 of the yeast Saccharomyces cerevisiae].
abstract: Usual "in vitro" mutagenesis tests combine microbial test systems with mammalian metabolism (microsomal assay). Some cases are known in which expected positive results are not obtained due to many factors operating between the microsomes in the incubation mixtures and the nucleus of the test microbial cells (detoxifying mechanisms, permeability effects, unstable intermediate, alternative targets in the pathway, etc.). In these cases, useful additional information could be obtained using microbial test systems with incorporated metabolism. Microbial systems and in particular yeasts in Cytochrome P-450 dependent metabolizing activity are known since many years. We studied under this aspect the strain D7 of Saccharomyces cerevisiae, used in our laboratory, in order to standardize the conditions for optimal metabolizing activity. The composition of the culture medium, the growth phase, and the effect of the amount of the initial inoculum, were studied. Cytochrome P-450 content was determined by the technique of difference spectra (reduced cytochrome +/- CO). Results on the effect of glucose and sodium phenobarbital concentration in the culture medium were in agreement with the literature. Moreover we found that the cytochrome P-450 contents was markedly dependent on the size of the initial inoculum, being higher and the smaller was the initial inoculum.
mesh_terms: D002455:Cell Division / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D003577:Cytochrome P-450 Enzyme System; D005947:Glucose; D010634:Phenobarbital
vernacular_title: Ruolo del citocromo P-450 nel ceppo D7 lievito Saccharomyces cerevisiae.