Many enzymes consist of a protein and a non-protein (called the cofactor). The proteins in enzymes are usually globular. The intra- and intermolecular bonds that hold proteins in their secondary and tertiary structures are disrupted by changes in temperature and pH. This affects shapes and so the catalytic activity of an enzyme is pH and temperature sensitive.
Everyday in the U.S. millions of cars and trucks idle needlessly, sometimes for hours. You may not be able to avoid keeping your engine running when youâre stopped at a traffic signal or stuck in slow-moving traffic. But other times idling is unnecessary. An idling car can release as much pollution as a moving car.
âAs an engine idles, the wear to consume one gallon of fuel is equal to driving up to 30 miles. In these situations, it is more effective to schedule future vehicle replacements or measure lifecycle costs based on the hours of engine operation or the amount of fuel burned over a period of time,â Korn said.