Complex sentence: Urocanic acid is an intermediate in the catabolism of L-histidine, from which it is formed through the action of histidine ammonialyase (also known as histidase or histidinase) by elimination of ammonium.
Split into simpler sentences: Urocanic acid is an intermediate in the catabolism of L-histidine. It is formed from L-histidine through the action of histidine ammonialyase (also known as histidase or histidinase) by elimination of ammonium.