At what substrate concentration would an enzyme with a kcat of 30.0 s-1 and a Km of 3. (а) 0.0050 M operate at one-quarter of its maximum rate? (b) trations [So]: ½ Km, 2 Km, and 10 Km. Determine the fraction of Vmax that would be obtained at the following substrate concen-
Catalysis and Enzymatic Reactions
Catalysis is the kind of chemical reaction in which the rate (speed) of a reaction is enhanced by the catalyst which is not consumed during the process of reaction and afterward it is removed when the catalyst is not used to make up the impurity in the product. The enzymatic reaction is the reaction that is catalyzed via enzymes.
Lock And Key Model
The lock-and-key model is used to describe the catalytic enzyme activity, based on the interaction between enzyme and substrate. This model considers the lock as an enzyme and the key as a substrate to explain this model. The concept of how a unique distinct key only can have the access to open a particular lock resembles how the specific substrate can only fit into the particular active site of the enzyme. This is significant in understanding the intermolecular interaction between proteins and plays a vital role in drug interaction.
![3. (а)
0.0050 M operate at one-quarter of its maximum rate?
At what substrate concentration would an enzyme with a kcat of 30.0 s-1 and a KM of
(b)
trations [So]: ½ Km, 2 KM, and 10 KM.
Determine the fraction of Vmax that would be obtained at the following substrate concen-
(c)
1 (HIV-1) has been the object of innumerable studies to develop
effective chemotherapeutic agents. It has been shown that p6*
known as the late assembly protein is an inhibitor of HIV protease.
An assay was developed using an artificial polypeptide substrate
containing a p-nitrophenylalanine residue at the cleavage point
that undergoes a small change in absorption at 295 nm upon bond
hydrolysis that could be followed spectrophotometrically. The
cleavage of the peptide bond is shown schematically on the right.
Results of the assay are given in the table below.
The protease of the human immunodeficiency virus-
Lys
NH2
Ala
Nle
Arg
Ala
Val-Nle-NH-CH-Ċ–NH-Glu
CH2
Lys
NH2
Ala
NO2
Nle
H2ON HIV-1 protease
Ala
Vo (nmole/min)
Arg
Vo
presence of
Val-Nle-NH-CH-COO-
+ NH-Glu
[S]
(nmole/min)
(µM)
10µM p6* pro-
CH2
tein
10
4.63
2.70
15
5.88
3.46
20
6.94
4.74
NO2
25
9.26
6.06
30
10.78
6.49
40
12.14
8.06
50
14.93
9.71](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F0740a5dc-b9fd-4c5c-ab7f-5d1415931eac%2F8ac068cb-1049-4e5b-b18f-496f8eff72aa%2Fkbuy02_processed.png&w=3840&q=75)
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