Occurrence of two different forms of protocatechuate 3,4-dioxygenase in a Moraxella sp

Journal Article · Wed Feb 01 00:00:00 EST 1989 · Applied and Environmental Microbiology; (USA)

OSTI ID:5102861

Sterjiades, R; Pelmont, J ^[1]

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1. Universite Grenoble (France)

Two alternative forms of protocatechuate 3,4-dioxygenase (PCase) have been purified from Moraxella sp. strain GU2, a bacterium that is able to grow on guaiacol or various other phenolic compounds as the sole source of carbon and energy. One of these forms (PCase-P) was induced by protocatechuate and had an apparent molecular weight of 220,000. The second form (PCase-G) was induced by guaiacol or other phenolic compounds, such as 2-ethoxyphenol or 4-hydroxybenzoate. It appeared to be smaller (M{sub r} 158,000), and its turnover number was about double that of the former enzyme. Both dioxygenases had similar properties and were built from the association of equal amounts of nonidentical subunits, {alpha} and {beta}, which were estimated to have molecular weights of 29,500 and 25,500, respectively. The ({alpha}{beta}){sub 3} and ({alpha}{beta}){sub 4} structures were suggested for PCases G and P, respectively. On the basis of two-dimensional gel electrophoresis, the {alpha} and {beta} polypeptides of PCase-G differed from those of PCase-P. Amino acid analysis supported this conclusion. Both PCases, however, had several other properties in common. It is proposed that both isoenzymes were generated from different sets of {alpha} and {beta} subunits, and the significance of these data is discussed.

• OSTI ID: 5102861
• Journal Information: Applied and Environmental Microbiology; (USA), Vol. 55:2; ISSN 0099-2240
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
BACTERIA
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BIODEGRADATION
CARBOXYLIC ACIDS
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550200* - Biochemistry