Study the given data and answer the questions that follow.
A sample of an enzyme called lactase was isolated from the intestinal lining of a calf. Assays were undertaken to evaluate the activity of the enzyme sample.
The substrate of lactase is the disaccharide lactose. Lactase breaks a lactose molecule in two, producing a glucose molecule and a galactose molecule.
Two assays were carried out.
`{:("Lactose concentration (% w/v)",15,15,15,15,15,15),("Concentration of enzyme smaple (%v/v)",0,5,10,15,20,25),("Reaction rate "mu"mole glucose "sec^(-1)mL^(-1),0,25,50,75,100,125):}`
`{:("Lactose concentration (% w/v)",0,5,10,15,25,30),("Concentration of enzyme smaple (%v/v)",5,5,5,5,5,5),("Reaction rate "mu"mole glucose "sec^(-1)mL^(-1),0,15,25,35,40,40):}`
Which of the following assays would you expect to have the highest reaction rate ?

Options

A. `{:("Lactose concentration (%w/v)","Concentration of enzyme sample (%v/v)"2),(" "15, " "5):}`
B. `{:("Lactose concentration (%w/v)","Concentration of enzyme sample (%v/v)"2),(" "30, " "5):}`
C. `{:("Lactose concentration (%w/v)","Concentration of enzyme sample (%v/v)"2),(" "15, " "25):}`
D. `{:("Lactose concentration (%w/v)","Concentration of enzyme sample (%v/v)"2),(" "30, " "25):}`

Answer

To determine which assay would have the highest reaction rate, we need to analyze the provided data regarding the enzyme lactase and its substrate lactose.

### Step-by-Step Solution:

1. **Understand the Enzyme-Substrate Relationship**:
- Lactase is an enzyme that breaks down lactose (a disaccharide) into glucose and galactose. The rate of reaction depends on both the concentration of the enzyme and the concentration of the substrate.

2. **Review the Assay Data**:
- **Assay 1**:
- Lactose concentration: 15% w/v
- Enzyme concentration: 0%, 5%, 10%, 15%, 20%, 25%
- Reaction rates: 0, 25, 50, 75, 100, 125 µmole glucose sec^(-1)mL^(-1)
- **Assay 2**:
- Lactose concentration: 0%, 5%, 10%, 15%, 25%, 30%
- Enzyme concentration: 5% (constant)
- Reaction rates: 0, 15, 25, 35, 40, 40 µmole glucose sec^(-1)mL^(-1)

3. **Identify Maximum Reaction Rates**:
- In **Assay 1**, the maximum reaction rate occurs at the highest enzyme concentration (25% v/v) with a reaction rate of 125 µmole glucose sec^(-1)mL^(-1).
- In **Assay 2**, the highest reaction rate is 40 µmole glucose sec^(-1)mL^(-1) at the highest lactose concentration (30% w/v).

4. **Compare the Maximum Rates**:
- The maximum reaction rate from Assay 1 (125 µmole glucose sec^(-1)mL^(-1)) is significantly higher than the maximum reaction rate from Assay 2 (40 µmole glucose sec^(-1)mL^(-1)).

5. **Conclusion**:
- Therefore, the assay with the highest reaction rate is **Assay 1** with a lactose concentration of 15% and an enzyme concentration of 25% v/v, yielding a reaction rate of 125 µmole glucose sec^(-1)mL^(-1).

### Final Answer:
**Assay 1** has the highest reaction rate.

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