All enzymes are not proteins. This statement is justified by: (A) All enzymes do not follow the Michaelis Menton hypothesis, (B) RNAs act as ribozymes, (C) Antibodies take part in the catalysis of many reactions, (D) Metals are involved in attachment to enzymes and catalysts
Answer is B. Ribozymes are RNA molecules with catalytic activities, which acts upon phosphodiester bonds in RNA & cause its hydrolysis . RNAs are not protein but meet all the classic criteria of the enzyme, therefore, all enzymes are not protein.