Arogenate dehydrogenase from Streptomyces phaeochromogenes. Purification and properties
Biological Chemistry Hoppe-Seyler
|November 1, 1985
Summary
Arogenate dehydrogenase from Streptomyces phaeochromogenes was purified. This enzyme is crucial for tyrosine biosynthesis and its properties were characterized.
Area of Science:
- Biochemistry
- Enzymology
- Microbiology
Background:
- Tyrosine biosynthesis is essential for microbial growth.
- Arogenate dehydrogenase is the final enzyme in this pathway.
- Understanding enzyme structure and function is key in biochemistry.
Purpose of the Study:
- To purify arogenate dehydrogenase from Streptomyces phaeochromogenes.
- To characterize the biochemical properties of the purified enzyme.
Main Methods:
- Enzyme purification using a five-step procedure.
- Molecular weight determination via SDS-PAGE and gel permeation chromatography.
- Isoelectric point (pI) determination.
- Kinetic analysis (Km values) for arogenate and NAD.
Main Results:
- Arogenate dehydrogenase was purified to homogeneity.
- The enzyme exists as a dimer with identical subunits (Mr 28,100 each).
- The native enzyme molecular weight was determined as 57,600 or 66,300.
- The enzyme's pI is 4.45.
- Km values for arogenate and NAD were determined as 0.105 mM and 0.01 mM, respectively.
Conclusions:
- The study successfully purified and characterized arogenate dehydrogenase.
- The enzyme's dimeric structure and kinetic parameters provide insights into tyrosine biosynthesis.
- This work contributes to the understanding of metabolic pathways in Streptomyces.
