Enzymes B – Chemistry

What holds substrate at active site?
chemical bonds
physical interactions
Describe lock and key model for enzymes
enzyme is rigid 3D body
Enzyme surface contains the active site
Describe the induced fit model.
Actie site becomes modified to accommodate the substrate
Which amino acids participate in teh active sites of more than 65% of enzymes
What occurs at the active site?
selection of a stereoisomer
What is at the active site of Trypsin?
A well for Lysine.
What is the well for that is created by Chymotrypsin?
Phenylalanine, Tryptophan, and Tyrosine
What factors affect teh rate of an enzyme-catalyzed reaction?
1. enzyme concentration
2. substrate concentration
3. temperature
4. pH
What is activation:
any process that initiates or increases the activity of an enzyme
What is inhibition:
any process that makes an active enzyme less active or inactive
What is a competitive inhibitor:
any substance that binds to the active site of an enzyme thereby preventing binding of substrate
What is a noncompetitive inhibitor
Any substanc hat binds to a portion of the enzyme othr than the active site and thereby inhibits the activity of the enzyme
Which has more of a detrimental effect on the enzyme- competitive inhibitor or noncompetitive inhibitor
noncompetitive inhibitor
An enzyme regulatin process where the product of a series of enzyme-catalyzed reactions inhibits an earlier reaction in the sequence. The inhibition may be cometitive or noncompetitive
Name an inactive form of an enzyme
How does an inactive form of an enzyme become activated?
Part of a polypeptide chain must be removed by hydrolysis to activate the enzyme
What is an example of a proteolytic enzyme
Trypsin (proteolytic enzyme) synthesized and stored as trypsinogen
How does the molecule achieve its active form?
Changing the primary structure changes the tertiary structure allowing the molecule to achieve its active form
What is Allosterism?
Enzyme regulation based on an event occurring at a place other than the active site but that creates a change in the active site
Do Allosteric enzymes have multiple polypeptde chains?
What is negative and positive modulation of an Allosteric enzyme
Negative -inhibition of an allosteric enzyme
Postivie-stimulation of an allosteric enzyme
What is a regulator in regard to an Allosteric enzyme?
A substance that binds to an allosteric enzyme
How does protein modification work with regard to enzyme regulation?
the process of affecting enzyme actibity by covalently modifying it….phosphorylation and dephosphorylation
What is an enzyme that occurs in multiple forms, each catalyzes the same reaction?
What is an example of an isoenzyme?
Lactate dehydrogenase catalyzes the oxidation of lactate to pyruvate
What medical diagnosis is made by Acid phosphatase?
Prostate cancer
What diagnosis is made by creatine phosphokinase ck?
heart attack
What diagnosis is made by amylase?
Pancreatic disease

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