There are 2 significant figures.
"Rule 3: Trailing zeros are significant if a decimal point is shown in the number, but may or may not be significant if no decimal point is shown."
Answer:
Enzyme is carbonic anhydrase
Substrate is 
Turnover number is 
Explanation:
An enzyme is used by a living organism as a catalyst to perform a specific biochemical reaction.
A substrate is a molecule upon which an enzyme acts.
Turnover number refers to the number of substrate molecules transformed by a single enzyme molecule per minute. Here, the enzyme is the rate-limiting factor.
Here,
Enzyme is carbonic anhydrase
Substrate is 
Turnover number is 