( Proteins ( ( are ( composed ( of ( ( ( long chains ) ( -LRB- ( polypeptides -RRB- ) ) ) ( of ( subunits ( ( ( called ( amino acids ) ) , ) ( with ( ( an average ) ( of ( ( ( about ( ( 400 or ) 500 ) ) ( amino ( acid molecules ) ) ) ( per protein ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNPS Proteins)) (VP (VBP are) (VP (VBN composed) (PP (IN of) (NP (NP (NP (JJ long) (NNS chains)) (PRN (-LRB- -LRB-) (NP (NNS polypeptides)) (-RRB- -RRB-))) (PP (IN of) (NP (NP (NNS subunits)) (VP (VBN called) (NP (JJ amino) (NNS acids)) (, ,) (PP (IN with) (NP (NP (DT an) (NN average)) (PP (IN of) (NP (NP (QP (RB about) (CD 400) (CC or) (CD 500)) (JJ amino) (NN acid) (NNS molecules)) (PP (IN per) (NP (NN protein)))))))))))))) (. .)))
Proteins are composed of long chains (polypeptides) of subunits called amino acids, with an average of about 400 or 500 amino acid molecules per protein.
(ROOT (S (NP (DT A) (NN protein)) (VP (VBZ is) (NP (NP (DT an) (JJ organic) (NN compound)) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (NP (JJ small) (NNS molecules)) (VP (VBN called) (NP (JJ amino) (NNS acids)))))))) (. .)))