This attachment only takes place if we have a coenzyme present attached onto that enzyme known as acetyl, coenzyme A or acetylCoA. So this enzyme is required for the CO2 to actually bind onto that biotin. And the coenzyme has to be bound onto that Pyruvate carboxylate for the step to actually take place. So we see that in the next step, the phosphorylated CO2 can now attach onto the biotin of the enzyme and form that carboxy biotin enzyme intermediate. So this intermediate here and so this bond that is formed between the carbon dioxide and the biotin that is bound onto the enzyme is actually a very reactive bond. It's a very high in energy bond.