Related Experiment Videos
Guinea pig brain histamine N-methyltransferase: purification and partial characterization
Journal of Neurochemistry
|July 1, 1983
Summary
Researchers purified histamine N-methyltransferase (HNMT) from guinea pig brain, characterizing its molecular weight, stability, and kinetic properties for histamine methylation. This enzyme is crucial for histamine metabolism.
Area of Science:
- Biochemistry
- Enzymology
Background:
- Histamine N-methyltransferase (HNMT) plays a key role in histamine metabolism.
- Understanding HNMT's properties is essential for studying histamine signaling pathways.
Purpose of the Study:
- To purify and characterize histamine N-methyltransferase (EC 2.1.1.8) from guinea pig brain.
- To determine the enzyme's kinetic parameters and physical properties.
Main Methods:
- Differential centrifugation
- Calcium phosphate adsorption
- DEAE-cellulose chromatography
- Affinity chromatography using S-adenosylhomocysteine-agarose
Main Results:
- HNMT was purified 4400-fold with a 12% yield, yielding a homogeneous protein.
- Apparent molecular weight was 29,000 ± 1000 Da; isoelectric point was 5.3.
- Km values for histamine and S-adenosyl-L-methionine were 13.57 ± 0.74 µM and 6.1 ± 0.12 µM, respectively. Ki for S-adenosyl-L-homocysteine was 24.5 ± 1.45 µM. pH optima were 7.5 and 9.0.
Conclusions:
- The study successfully purified and characterized guinea pig brain HNMT.
- The determined kinetic parameters provide insights into the enzyme's function in histamine metabolism.