CHMB62H3 Chapter 7: Chap 7 Questions .docx
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Many isolated enzymes, if incubated at 37 c, will be denatured. However, if the enzymes are incu- bated at 37 c in the presence of substrate, the enzymes are catalytically active. Succinylcholine is a fast-acting, short-duration muscle relaxant that is used when a tube is inserted into a patient"s trachea or when a bronchoscope is used to examine the trachea and bronchi for signs of cancer. Within seconds of the administration of succinylcholine, the patient experiences muscle paralysis and is placed on a respi- rator while the examination proceeds. Succinylcholine is a competitive inhibitor of acetylcholinesterase, a nervous sys- tem enzyme, and this inhibition causes paralysis. However, succinylcholine is hydrolyzed by blood-serum cholinesteraswhich shows a broader substrate specificity than does the ner- vous system enzyme. Paralysis lasts until the succinylcholine is hydrolyzed by the serum cholinesterase, usually several minutes later. (a) as a safety measure, serum cholinesterase is measured before the examination takes place.
