Getting a Reaction (image) Rockefeller University Share Print E-Mail Caption An enzyme responsible for a crucial step in the production of cholesterol has ten segments that span the cell membrane in which it is embedded. These contain two pockets the enzyme uses to bring the reactants together. Credit Laboratory of Cell Biology at The Rockefeller University/Nature Usage Restrictions Image may only be used to illustrate research described in the accompanying story. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.