Question

The enzyme dihydrofolate reductase (DHFR) normally resides in the cytosol, and it can be imported into mitochondria by appending a mitochondrial signal sequence. However, when this modified DHFR is incubated with methotrexate, which is a substrate analog that binds tightly to the active site, the modified DHFR is no longer imported. Propose an explanation for this finding.

Name: the enzyme dihydrofolate reductase dhfr normally resides in the cytosol and it can be imported into mitochondria by appending a mitochondrial signal sequence however when this modified dhfr 94652
Uploaded: 2022-05-10T10:08:13-08:00
Duration: 2 min 27 s
Channel: Shaiju T
Description: the enzyme dihydrofolate reductase dhfr normally resides in the cytosol and it can be imported into mitochondria by appending a mitochondrial signal sequence however when this modified dhfr 94652

          The enzyme dihydrofolate reductase (DHFR) normally resides in the cytosol, and it can be imported into mitochondria by appending a mitochondrial signal sequence. However, when this modified DHFR is incubated with methotrexate, which is a substrate analog that binds tightly to the active site, the modified DHFR is no longer imported. Propose an explanation for this finding.

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Biology for AP Courses

Julianne Zedalis, John Eggebrecht

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Solved by Expert Shaiju T

05/10/2022

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Step 1: The enzyme dihydrofolate reductase (DHFR) normally resides in the cytosol and can be imported into mitochondria by appending a mitochondrial signal sequence. Show more…

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The enzyme dihydrofolate reductase (DHFR) normally resides in the cytosol, and it can be imported into mitochondria by appending a mitochondrial signal sequence. However, when this modified DHFR is incubated with methotrexate, which is a substrate analog that binds tightly to the active site, the modified DHFR is no longer imported. Propose an explanation for this finding.