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.
Four ways to be idle-free. Turn off your ignition if youâre waiting more than 10 seconds. Contrary to popular belief, restarting your car does not burn more fuel than leaving it idling. In fact, idling for just 10 seconds wastes more gas than restarting the engine. Warm up your engine by driving it, not by idling. Todayâs electronic engines do not need to warm up, even in winter.