Proline biosynthesis in Escherichia coli. Purification and characterisation of glutamate-semialdehyde dehydrogenase.
Glutamate-semialdehyde dehydrogenase, catalysing the reduction in vivo of gamma-glutamyl phosphate to glutamate 5-semialdehyde in the pathway of proline biosynthesis in Escherichia coli, has been purified to homogeneity. High initial levels of the enzyme were achieved by using a multicopy ColEl-pro A, B hybrid plasmid. The protein has a molecular weight of 1.89 X 10(5) and consists of four identical subunits of molecular weight 4.7 X 10(4) each. The pH optimum is 7.0 and the protein is stable for at least 10 min between pH 6.0-9.0 and for long periods at pH 7.0 It is rapidly inactivated at temperatures greater than 50 degrees C. The enzyme is very sensitive to inhibition by p-chloro-mercuribenzoate, copper and nickel ions.
D000445:Aldehyde Oxidoreductases / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D050698:Glutamate-5-Semialdehyde Dehydrogenase; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008970:Molecular Weight; D011392:Proline / Q000096:biosynthesis*; D013696:Temperature
D046911:Macromolecular Substances; D011392:Proline; D000445:Aldehyde Oxidoreductases; D050698:Glutamate-5-Semialdehyde Dehydrogenase