Methods and compositions relating to the engineering of an improved protein with methionine-?-lyase enzyme activity are described. For example, in certain aspects there may be disclosed a modified cystathionine-?-lyase (CGL) comprising one or more amino acid substitutions and capable of degrading methionine. Furthermore, certain aspects of the invention provide compositions and methods for the treatment of cancer with methionine depletion using the disclosed proteins or nucleic acids.
