Enzymatic pattern processing

A table-top prototype has been constructed that uses the enzyme malate dehy drogenase to recognize input signal patterns. The device is controlled by t he enzyme in response to injection of Mg2+ used as a signaling substance. O utput is monitored spectroscopically. If Mg2+ is injected along either of t wo signal lines (i.e., if the input signal pattern is 10 or 01) the device emits an output of 1. Injection along neither or both lines results in an o utput of 0. The enzyme in effect is used as a transform that converts the l inearly inseparable exclusive-or problem into a linearly separable problem.