The present invention provides a thermoplastic vulcanizate prepared by a process comprising the steps of dynamically vulcanizing rubber within a blend that includes the rubber and a thermoplastic resin, where the rubber comprises an elastomeric copolymer of ethylene, at least one -olefin, and optionally one or more diene monomers, where the elastomeric copolymer is characterized by having a crystallinity, as measured by differential scanning calorimetry, of less than 10 J/g, an ethylene content that is less than 90 mole percent based upon the entire copolymer, a weight average molecular weight that is greater than about 20,000 as measured by GPC with polystyrene standards, a molecular weight distribution that is less than 7, and an ethylene compositional distribution that is less than about 4 percent for the closest 90 percent of fractioned samples.