The turnover number for your enzyme is "90.9 min"^(-1).
The turnover number, or K_"cat", expresses how many substrate molecules are converted to product by the enzyme per unit time. Moreover, the turnover number is calculated when the enzyme has maximum efficiency -> V_"max".
K_"cat" = V_"max"/([E]), where
[E] - the total concentration of enzyme present.
Since V_"max" uses mu"mol" and the concentration of the enzyme is given in "nmol", I'll convert the latter to mu"mol"
121cancel("nmol") * (10^(-3)mu"mol")/(1cancel("nmol")) = 121 * 10^(-3)mu"mol"
Once again, plug and play
K_"cat" = (11.0cancel(mu"mol") * "min"^(-1))/(121 * 10^(-3)cancel(mu"mol")) = "90.9 min"^(-1)