The invention disclosed herein relates to methods and materials for producing simvastatin and related compounds such as huvastatin. In particular, the disclosure teaches that variants of the LovD acyltransferase polypeptide can be engineered to exhibit properties that facilitate their use in the production of simvastatin and/or huvastatin. The materials and processes disclosed herein are designed so that fermentation facilitates lovastatin being converted to simvastatin and related compounds with minimal modifications.