30 Questions
What is the term used to refer to the area on the enzyme where the substrate attaches?
Active site
What is the term for the substance at the beginning of an enzymatic reaction on which an enzyme acts?
Substrate
Which type of enzyme is inactive without its non-protein moiety?
Apoenzyme
What do we call a non-protein chemical compound tightly bound to an enzyme by covalent bonds?
Prosthetic group
What is the term for the special pocket or cleft in enzyme molecules where substrates bind?
Active site
What is the term for a group of enzymes that are active with their non-protein component?
Holoenzyme
What is the purpose of using 1-fluoro-2-4-dinitrobenzene in amino acid sequencing?
To label the first amino acid in a polypeptide chain
What is the limitation of using the Sanger reagent in amino acid sequencing?
It destroys the rest of the polypeptide chain
What is the role of the phenylisothiocyanate reagent in Edman degradation?
To label the first amino acid in a polypeptide chain
What is the advantage of using Edman degradation over the Sanger reagent?
It does not destroy the rest of the polypeptide chain
What is the significance of determining the amino acid sequence of a polypeptide?
It determines the structure of the protein
Who is credited with the development of the Sanger reagent?
Fred Sanger
What role do enzymes play in increasing reaction rates?
Decreasing activation energy
Which model of enzyme action involves a flexible active site?
Induced Fit Model
What does the Lock-and-Key Model of enzyme action state about the relationship between active sites and substrates?
Active site has a rigid shape and only specific substrates fit
Which type of enzymes show a greater range of substrate specificity according to the models discussed?
Enzymes following the Induced Fit Model
When a substrate fits into an enzyme's active site, which complex is formed?
Enzyme-Substrate Complex (ES)
What is the overarching effect of enzymes on reaction rates?
Increase the rate of reaction
What is the typical pH range at which most enzymes have an optimum pH?
6 - 8 (near neutral)
Which factor can denature enzymes due to high values?
Extreme pH
What occurs when an enzyme reaches saturation with substrate molecules?
The reaction rate levels off
Which of the following is an example of a cofactor for proper enzymatic activity?
Minerals (e.g., zinc)
What do competitive inhibitors do to enzymes?
Prevent the active site from binding to the substrate
In enzymatic reactions, what happens when the substrate concentration increases?
The reaction rate increases until all enzyme molecules are in use
What is the reagent that reacts with primary amino groups in both aliphatic and aromatic amines to produce stable blue- or blue-green fluorescent sulfonamide adducts?
Dansyl Chloride
Which enzyme cleaves peptide bonds on the carboxyl side of aromatic amino acids like Phenylalanine, Tyrosine, and Tryptophan?
Chymotrypsin
What is the reagent that cleaves at tryptophan (Trp) residues?
CNBr
Which enzyme breaks down collagen in meat, making it tender?
Papain
What reacts with secondary amines and is more useful for samples containing brominated amino acids?
Dansyl Chloride
What cleaves at the peptide bond on the carboxyl side of Arginine and Lysine?
Trpsin
Test your knowledge on sequencing polypeptides to determine the amino acid present at the beginning of the sequence. Learn about using chemical reactions and proteolytic enzymes for sequencing, including the Sanger reagent. Explore how Nobel prize-winning research on insulin sequence was conducted under slightly alkaline conditions.
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