Related Experiment Videos
Identification of a novel reductase in folate metabolism
S P Rothenberg1, D Kyner, G Solomon
1Department of Medicine, Department of Veterans Affairs Medical Center, Brooklyn, NY.
Abstract:
A protein with a molecular weight of 27,500 was co-purified with the enzyme dihydrofolate reductase (molecular weight 22,000) from the liver of mice less than 8 weeks of age using a methotrexate-Sepharose affinity matrix. This 27.5 kDa protein crossreacts with dihydrofolate reductase against an antiserum raised to the purified 22 kDa enzyme. The protein could also reduce dihydrofolate to tetrahydrofolate, thus demonstrating the catalytic properties of dihydrofolate reductase. The expression of this 27.5 kDa protein also appears to be age-dependent because it could not be isolated from liver of mice older than four months.
Insights
Researchers discovered a novel 27.5 kDa protein co-purifying with dihydrofolate reductase (DHFR) in young mice liver. This protein exhibits DHFR enzymatic activity and its expression is age-dependent.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Dihydrofolate reductase (DHFR) is a critical enzyme in folate metabolism.
- Understanding DHFR's interactions and regulatory mechanisms is essential for various biological processes.
Purpose of the Study:
- To identify and characterize proteins co-purifying with dihydrofolate reductase.
- To investigate the enzymatic activity and expression patterns of associated proteins.
Main Methods:
- Affinity purification using methotrexate-Sepharose matrix.
- Immunological cross-reactivity assays using antiserum against purified DHFR.
- Enzymatic assays to determine dihydrofolate reduction activity.
Main Results:
- A 27.5 kDa protein was co-purified with 22 kDa DHFR from young mouse liver.
- The 27.5 kDa protein showed immunological cross-reactivity with DHFR.
- This protein demonstrated catalytic activity, reducing dihydrofolate to tetrahydrofolate.
- Expression of the 27.5 kDa protein was age-dependent, absent in older mice.
Conclusions:
- A novel protein with DHFR-like enzymatic activity exists and associates with DHFR.
- This protein's expression is regulated by age in mice.
- The findings suggest a potential regulatory role or complex formation involving DHFR.