The enzyme alkaline phosphatase catalyses the conversion of -glycerophosphate to glycerol and inorganic phosphate (P_i).

To characterise alkaline phosphatase isolated from a new organism, a 10 minute reaction using 0.5 ml of enzyme sample, and -glycerophosphate substrate was carried out at 37^oC. The inorganic phosphate (P_i) released during the reaction was then measured by absorbance in an assay for P_i. It was determined using a standard curve for P_i that 6 mol of P_i was released during the 10 minute reaction.

Which of the following values is correct for the activity of alkaline phosphatase in the enzyme sample, expressed as mol of P_iproduced per minute per ml of enzyme?

1. 6.0
2. 12.0
3. 0.12
4. 1.2