( ( The ( hammerhead ribozyme ) ) ( ( is ( ( bound ( to ( ( ( ( a ( protein carrier ) ) , ) transferin ) , ) ) ) ( by polylysine ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ hammerhead) (NN ribozyme)) (VP (VBZ is) (VP (VBN bound) (PP (TO to) (NP (NP (DT a) (NN protein) (NN carrier)) (, ,) (NP (NN transferin)) (, ,))) (PP (IN by) (NP (NN polylysine))))) (. .)))
The hammerhead ribozyme is bound to a protein carrier, transferin, by polylysine.
(ROOT (S (NP (NP (DT The) (NN discovery)) (PP (IN of) (NP (NNS ribozymes)))) (VP (VBD nullified) (NP (DT the) (NN idea)) (SBAR (IN that) (S (NP (DT all) (JJ biological) (NNS catalysts)) (VP (VBP are) (NP (NNS proteins)))))) (. .)))