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B6db references: pcearae

type Journal Article
authors Hoffmann, K.; Schneider-Scherzer, E.; Kleinkauf, H.; Zocher, R.
title Purification and characterization of eucaryotic alanine racemase acting as key enzyme in cyclosporin biosynthesis
journal J Biol Chem
ui Pcearae
year (1994)
volume 269
number 17
pages 12710-4
keywords Alanine Racemase/*isolation & purification/metabolism
abstract A specific alanine racemase, which is a key enzyme in the biosynthesis of the undecapeptide cyclosporin A, was purified to electrophoretic homogeneity from the fungus Tolypocladium niveum. This is the first enzyme of this kind isolated from a eucaryotic organism. The enzyme catalyzes the reversible racemization of alanine and requires pyridoxal phosphate as the exclusive cofactor. Km values for L- and D-alanine were found to be 38 and 2 mM, respectively. Maximal reaction velocity was observed at 42 degrees C and pH 8.8 for the L to D direction. Molecular mass determinations of the denatured enzyme by SDS-polyacrylamide gel electrophoresis gave a value of 37 kDa, whereas gel filtration calibration studies yielded a value between 120 and 150 kDa, indicating an oligomeric native structure.
last changed 2008/05/15 18:54

B6db references