tokens: These genes were expressed in a Saccharomyces cerevisiae mutant in which the endogenous ferrochelatase gene ( HEM15 ) had been deleted , and the phenotypes of the transformants were characterized .
folded_tokens: these gene be express in a saccharomyces cerevisiae mutant in which the endogenous ferrochelatase gene ( hem15 ) have be delete , and the phenotype of the transformant be characterize .