what type of reaction is catalyzed by proteases - -hydrolysis
-what metal iron is required by carbonic anhydrases for activity - -Zn2+
-What metal
... [Show More] ion is frequently found in enzyme sites that act on phosphate containing substrates - -Mg2+
-The catalytic mechanism of carbonic anhydrase, in which the substrate are simply oriented to stabilize the transition state, is called ______ - -catalysis by approximation
-the mechanism of chymotrypsin involves the formation of an unstable ________- shaped intermediate that is stabilized by the oxyanion hole - -tetrahedral
-in trypsin, the specificity pocket contains a/an _________ residue that binds to the positive charge of the K or R residue of that substrate - -aspartyl, aspartic, or D
-The reaction center of most carbonic anhydrases in a zinc ion bound to water _______ residues of the enzyme - -histidine
-In chymotrypsin, the tetrahedral intermediate transition state is stabilized by a structural feature referred to as the "___________________" hole. - -oxyanion
-in proteases such as papain, a _________ residue is activated by hydrogen-bonding to a histidine residue - -cysteine
-Myosins hydrolyze _____________ in a controlled manner and use the free energy of hydrolysis to promote conformational changes within myosin itself. - -ATP
-Which amino acids in chymotrypsin are found in the active site and are participants in substrate cleavage - -His, Ser, Asp
-how specificity is determined by chymotrypsin - -binding of the proper amino acid into deep pocket on the enzyme
-Where does cleavage of the scissile bond by chymotrypsin occur? - -on the C-terminal side of a Phe or Trp residue
-Which of the following is NOT a way in which enzymes stabilize a transition state? - -causing the temperature of the environment to increase
-Convergent evolution is attributed to similarities found between - -chymotrypsin and subtilisin
-the metal ion most commonly found at the active site of metalloproteases is - -zinc
-Carbonic anhydrases are necessary becuase - -spontaneous hydration and dehydration of carbon dioxide are rapid, but not at speeds necessary for biochemical processes, and hydration and dehydration of carbon dioxide are sometimes coupled to other biochemical processes.
-binding of a water molecule to the zinc ion induces - -a lowered pKa for water, which leads to formation of a zinc bound hydroxide ion.
-type II restriction enzymes cut - -double-stranded DNA, forming a 5' phosphoryl group and a 3' hydroxyl group on each strand.
-myosins function to - -couple ATP hydrolysis to large conformational changes
-metal ion catalysis is facilitated by any of several mechanisms, including:
A) stabilizing negative charges on an intermediate.
B) promoting formation of nucleophiles.
C) metals binding directly to substrates.
D) stabilizing negative charges on an intermediate and metals binding directly to substrates.
E) All of the answers are correct. - -E) All of the answers are correct.
-What is the challenge for a protease to facilitate hydrolysis of a peptide bond - -the peptide bond contains a carbonyl that is very reactive; therefore, the catalytic mechanism must employ a feature that promotes nucleophilic attack of the carbonyl group by a strong nucleophile so the peptide bond can be cleaved
-what caused a "burst" of activity followed by a steady-state reaction when chymotrypsin was studied by stop-flow techniques (i.e. pre-steady state experiment) - -chymotrypsin cleaves peptide bonds in a two-step reaction, in which the first step, formation of the acyl enzyme intermediate, is faster than the second step, hydolysis
-what is the common strategy for cysteine, metallo-, and aspartyl proteases? - -all employ a mechanism whereby a nucleophile is generated that attacks the carbonyl carbon of the peptide bond
-what is the common nucleophile found in cysteine, metallo-, and aspartyl proteases? - -the common nucleophile is water
-how is bicarbonate formed when carbonic anhydrase is present - -the zinc promotes formation of hydroxide ion, which attacks the carbon dioxide
-what features of carbonic anhydrase allow the rapid hydration of carbon dioxide - -Bringing the [Show Less]