type	Journal Article
authors	van der Meer, R. A.; Groen, B. W.; Duine, J. A.
title	On the biosynthesis of free and covalently bound PQQ. Glutamic acid decarboxylase from Escherichia coli is a pyridoxo-quinoprotein
journal	FEBS Lett
Activity	4.1.1.15
ui	89211380
year	(1989)
volume	246
number	1-2
pages	109-12.
keywords	Chromatography, High Pressure Liquid
abstract	Analysis of glutamic acid decarboxylase (GDC) (EC 4.1.1.15) from Escherichia coli ATCC 11246 revealed the presence of six pyridoxal phosphates (PLPs) as well as six covalently bound pyrroloquinoline quinones (PQQs) per hexameric enzyme molecule. This is the second example of a pyridoxo-quinoprotein, suggesting that other atypical pyridoxoproteins (PLP-containing enzymes) have similar cofactor composition. Since the organism did not produce free PQQ and its quinoprotein glucose dehydrogenase was present in the apo form, free PQQ is not used in the assemblage of GDC. Most probably, biosynthesis of covalently bound cofactor occurs in situ via a route which is different from that of free PQQ. Thus, organisms previously believed to be unable to synthesize (free) PQQ could in fact be able to produce quinoproteins with covalently bound cofactor. Implications for the role of PQQ in eukaryotic cells are discussed.
last changed	2002/11/12 16:17