▁identify ▁any ▁protein ▁associated ▁with ▁the ▁sp lic ing ▁reaction . ▁After ▁much ▁work , ▁C ech ▁proposed ▁that ▁the ▁intr on ▁sequence ▁portion ▁of ▁the ▁R NA ▁could ▁break ▁and ▁reform ▁ph osph odi ester ▁b onds . ▁At ▁about ▁the ▁same ▁time , ▁Sid ney ▁Alt man , ▁a ▁professor ▁at ▁Y ale ▁University , ▁was ▁studying ▁the ▁way ▁t R NA ▁mole cules ▁are ▁processed ▁in ▁the ▁cell ▁when ▁he ▁and ▁his ▁colle agues ▁isolated ▁an ▁en zym e ▁called ▁R N ase - P , ▁which ▁is ▁responsible ▁for ▁conversion ▁of ▁a ▁prec ursor ▁t R NA ▁into ▁the ▁active ▁t R NA . ▁Much ▁to ▁their ▁surprise , ▁they ▁found ▁that ▁R N ase - P ▁contained ▁R NA ▁in ▁addition ▁to ▁protein ▁and ▁that ▁R NA ▁was ▁an ▁essential ▁component ▁of ▁the ▁active ▁en zym e . ▁This ▁was ▁such ▁a ▁foreign ▁idea ▁that ▁they ▁had ▁difficulty ▁publishing ▁their ▁find ings . ▁The ▁following ▁year , ▁Alt man ▁demonstrated ▁that ▁R NA ▁can ▁act ▁as ▁a ▁catal yst ▁by ▁showing ▁that ▁the ▁R N ase - P ▁R NA ▁sub unit ▁could ▁catal y ze ▁the ▁cle av age ▁of ▁prec ursor ▁t R NA ▁into ▁active ▁t R NA ▁in ▁the ▁absence ▁of ▁any ▁protein ▁component . ▁ ▁Since ▁C ech ' s ▁and ▁Alt man ' s ▁discovery , ▁other ▁investig ators ▁have ▁discovered ▁other ▁examples ▁of ▁self - cle aving ▁R NA ▁or ▁catal yt ic ▁R NA ▁mole cules . ▁Many ▁rib oz