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Applied and Environmental Microbiology, May 2000, p. 2045-2051, Vol. 66, No. 5
Microbiology Department, Swiss Federal
Institute for Environmental Science and Technology (EAWAG), and
Swiss Federal Institute of Technology (ETH), CH-8600 Duebendorf,
Switzerland
Received 6 January 2000/Accepted 9 March 2000
In vitro enzyme-based ATP regeneration systems are important for
improving yields of ATP-dependent enzymatic reactions for preparative
organic synthesis and biocatalysis. Several enzymatic ATP regeneration
systems have been described but have some disadvantages. We report here
on the use of polyphosphate:AMP phosphotransferase (PPT) from
Acinetobacter johnsonii strain 210A in an ATP regeneration system based on the use of polyphosphate (polyP) and AMP as substrates. We have examined the substrate specificity of PPT and demonstrated ATP
regeneration from AMP and polyP using firefly luciferase and hexokinase
as model ATP-requiring enzymes. PPT catalyzes the reaction polyPn + AMP
0099-2240/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
In Vitro ATP Regeneration from Polyphosphate
and AMP by Polyphosphate:AMP Phosphotransferase and Adenylate
Kinase from Acinetobacter johnsonii 210A
ADP + polyPn
1. The ADP can be
converted to ATP by adenylate kinase (AdK). Substrate specificity with nucleoside and 2'-deoxynucleoside monophosphates was examined using partially purified PPT by measuring the formation of nucleoside diphosphates with high-pressure liquid chromatography. AMP and 2'-dAMP
were efficiently phosphorylated to ADP and 2'-dADP, respectively. GMP,
UMP, CMP, and IMP were not converted to the corresponding diphosphates
at significant rates. Sufficient AdK and PPT activity in A. johnsonii 210A cell extract allowed demonstration of
polyP-dependent ATP regeneration using a firefly luciferase-based
ATP assay. Bioluminescence from the luciferase reaction, which normally
decays very rapidly, was sustained in the presence of A. johnsonii 210A cell extract, MgCl2,
polyPn=35, and AMP. Similar reaction mixtures containing strain 210A cell extract or partially purified PPT, polyP,
AMP, glucose, and hexokinase formed glucose 6-phosphate. The results
indicate that PPT from A. johnsonii is specific for AMP and
2'-dAMP and catalyzes a key reaction in the cell-free regeneration of
ATP from AMP and polyP. The PPT/AdK system provides an alternative to
existing enzymatic ATP regeneration systems in which
phosphoenolpyruvate and acetylphosphate serve as phosphoryl donors and
has the advantage that AMP and polyP are stabile, inexpensive substrates.
*
Corresponding author. Mailing address: The Dow Chemical
Company, 5501 Oberlin Dr., San Diego, CA 92121. Phone: (858) 352-4410. Fax: (858) 352-4450. E-mail: smresnick{at}dow.com.
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