The phosphorylation state of a human protein follows the oscillatory pattern shown in the first graph below. The protein is phosphorylated by two kinases (1 and 2), both of which are activated in an oscillatory pattern. Kinase 1 oscillates in congruence with the circadian rhythm, while kinase 2 oscillates at a higher frequency and is independent of the circadian clock. The second graph shows the phosphorylation state of the same protein in mutant cells lacking one of the kinases mentioned above. Which kinase (1 or 2) do you think is missing in these mutant cells? Write down 1 or 2 as your answer.