V. Y. Chernyak and N. A. Sinitsyn We explore quantization of the response of a molecular motor to periodic modulation of control parameters. We formulate the pumping-quantization theorem (PQT) that identifies the conditions for robust integer quantized behavior of a periodically driven molecular machine. Implication of PQT on experi ... [J. Chem. Phys. 131, 181101 (2009)] published Tue Nov 10, 2009.