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Rat histamine N-methyltransferase. Quantification, tissue distribution, purification, and immunologic properties
The Journal of Biological Chemistry
|October 25, 1983
Summary
Researchers quantified histamine N-methyltransferase activity across 25 rat tissues using a new assay. They purified the enzyme, revealing its molecular weight and optimal pH, and confirmed shared antigenic determinants between neuronal and non-neuronal forms.
Area of Science:
- Biochemistry
- Enzymology
- Pharmacology
Background:
- Histamine N-methyltransferase (HNMT) is crucial for histamine inactivation in mammals.
- Understanding HNMT distribution and properties is key to histamine metabolism research.
Purpose of the Study:
- To develop a sensitive assay for HNMT activity.
- To quantify HNMT activity in various rat tissues.
- To purify and characterize renal HNMT.
Main Methods:
- Developed a sensitive and specific assay for HNMT.
- Quantified HNMT activity in 25 rat tissues.
- Purified renal HNMT using affinity chromatography with histamine elution.
- Determined enzyme molecular weight and pH dependency.
- Generated antibodies to renal HNMT for immunoprecipitation studies.
Main Results:
- HNMT activity was quantified in 25 rat tissues.
- Purified renal HNMT exhibited a molecular weight of 33,400 Da.
- The enzyme showed optimal activity at pH 8.0-8.25.
- Antibodies to renal HNMT also recognized the brain enzyme, indicating shared epitopes.
Conclusions:
- HNMT activity varies across rat tissues.
- Purified HNMT has specific biochemical properties.
- Neuronal and non-neuronal HNMT share common antigenic determinants, suggesting structural similarities.