type	Journal Article
authors	Cecchini, G.; Bojanowski, R. J.; Demoss, R. D.
title	Tryptophanase from Sphaerophorus funduliformis. Purification, molecular weight and subunit properties
journal	Biochim Biophys Acta
Activity	4.1.99.1
ui	75146778
year	(1975)
volume	386
number	1
pages	340-51.
keywords	Amino Acids/analysis
abstract	A crystalline tryptophanase can be obtained from extracts of Spaerophorus funduliformis using a heat treatment, hydroxyapatite chromatography and solubility in solutions of (NH4)2SO4 as a function of pH and temperature. The purified enzyme is homogeneous by several criteria. S. funduliformis tryptophanase has a specific activity of 11.5-13.5 and requires pyridoxal 5'-phosphate for enzymatic activity. Like other tryptophanases that have been studied, the S. funduliformis enzyme is a tetramer protein consisting of four apparently identical subunits. The native enzyme has a sedimentation coefficient of 11.2 S and a molecular weight of 244 000. In solutions of 5 M guanidine - HCl, 8 M urea, and sodium dodecylsulfate, at high pH or in the presence of thiols, the enzyme dissociates to 59 000 molecular weight species which are homogeneous by the criterion of weight. Peptide maps of the reduced holo-tryptophanase show one pyridoxal-containing peptide and, lacking agreement with the determined amino acid composition, suggest that the subunits of the enzyme contain a high degree of internal sequence homology.
last changed	2002/11/12 16:17