Lipase is a digestive enzyme produced by the pancreas that catalyses the hydrolysis of dietary lipids. The table shows how the pH of a liquid food containing a high proportion of lipids decreases over time. [Figure 14] Which statements are possible explanations of the results of the experiment between 50 and 60 minutes? 1 Enzyme concentration becomes the limiting factor. 2 Substrate concentration becomes the limiting factor. 3 All the enzyme active sites are saturated. 4 Denaturation of the enzyme by the products. 5 Products are acting as competitive inhibitors.