Biochemistry : Hydrolases
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Example Question #1 : Protein Functions
Lysosomal enzymes are predominantly __________.
isomerases
decarboxylases
kinases
hydrolases
oxidases
hydrolases
The lysosome is the "stomach" of the cell. It contains many hydrolytic enzymes to digest and recycle the monomers used to form old polymers. Remember the opposite of dehydration/condensation synthesis is hydrolysis. Hydrolysis reactions use water to break bonds in polymers, yielding monomers that can be recycled and reused in anabolic pathways.
Example Question #2 : Hydrolases
Which of the following best describes how a lysozyme works?
It cleaves the phosphodiester bond in nucleic acids, via hydrolysis.
It is responsible for the cleaving of amino acid chains via the ping-pong mechanism.
It cuts a polysaccharide relatively slowly, facilitating a random, spontaneous collision between water and the sugar, with little intervention.
It hydrolyzes bonds in lipids, causing a split in a fatty acid chain.
It cuts the bond in a polysaccharide, by holding six sugars in a row in its active site, and adding a water molecule, causing hydrolysis.
It cuts the bond in a polysaccharide, by holding six sugars in a row in its active site, and adding a water molecule, causing hydrolysis.
Lysozymes speed up by many times the hydrolysis of polysaccharides, by adding the water molecule to sugars linked in its enzyme-substrate complex. If left alone without the lysozyme, this hydrolysis would occur relatively infrequently, because it requires a large activation energy which would be supplied only by rare random collisions. The amino acid cleavage enzyme which uses the ping-pong mechanism is chymotrypsin. The enzyme which breaks nucleic acid phosophodiester bonds is phosphodiesterase. Fats are hydrolyzed by lipases, not lysozymes.
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