The reason they want you to use a science professor or any professor to write a LOR is so that the Ad Coms gain an understanding of your performance through the eyes of the teacher... So unless this person taught you I don't think it is a good idea. The only exception would be if you plan to find another professor that did teach you to write an LOR, and the one you're speaking of could be used as someone that can account for your characterization from a more personal perspective.