Enzymes are biocatalysts that catalyse reactions at very high rates compared to chemical catalysts. They are specific to the substrate and reaction they catalyse. A few statements about enzymes are made below:

(i) Not every enzyme is proteinaceous in nature.

(ii) Some RNAs also are enzymes.

(iii) The active site of the enzyme is complementary to the transition state.

(iv) Enzymes alter the equilibrium constant of the reaction.

(v) Enzymes catalyse only irreversible reactions.

Which of the above statements are true?