Vectors, host cells, and methods are provided for the production of proteins in yeast. The vectors generally contain a selection gene, a yeast 2 micron sequence, and a polynucleotide encoding a polypeptide, where the polynucleotide is operably linked to promoter, and where the polynucleotide contains one or more yeast-preferred codons. Host cells are cultured under conditions where, after an initial batch phase, oxygen concentration is kept high and glucose feed is regulated so that the yeast cells stay in respiratory metabolism.