Isolation and molecular analysis of the gene for cytochrome c1 from Kluyveromyces lactis.

By ethyl methanesulphonate mutagenesis of the yeast Kluyveromyces lactis we have isolated five nuclear mutants that were unable to grow on non-fermentable carbon sources. The mutations were found to belong to three complementation groups. After functional complementation of the mutation in one of these mutants we have cloned the structural gene for cytochrome c1, named KlCYT1. This gene has been assigned to chromosome VI and its nucleotide sequence exhibited 74.3% identity to the homologous gene of S. cerevisiae.