Six large catalytic molecules in the interior do the work, and six small regulatory molecules on the outside control how fast the catalytic units work.

The catalytic cracking unit, used to break crude oil down into usable products like gasoline, was at the center of the blast.

The refinery also has an HF Alkylation unit, catalytic reforming unit and three hydrotreating type units.

These protein kinases are present as tetramers with two regulatory units and two catalytic units.

Another way to desensitize is to uncouple the regulatory and catalytic units of the cAMP system.

Upon binding of cAMP to the regulatory units, the catalytic units are released and initiate the phosphorylation of proteins, leading to the physiologic action.

The enzyme consists of two duplicated catalytic units and one structural unit encoded on a single gene, representing a novel three-unit architecture.

The alpha-subunit is the catalytic unit and contains regions characteristic of serine/threonine protein kinases.

The explosion was caused by a catalytic cracking unit that blew up at the Shell refinery.

It began with three units; the distillation unit, a topping unit, and cracking catalytic unit.