Microbial metabolism of amino alcohols. 1-Aminopropan-2-ol and ethanolamine metabolism via propionaldehyde and acetaldehyde in a species of Pseudomonas

Abstract

1. Growth and manometric experiments showed that a Pseudomonas sp. P6 (N.C.I.B. 10431), formerly known as Achromobacter sp. P6, was capable of growth on both stereoisomers of 1-aminopropan-2-ol, and supported the hypothesis that assimilation involved metabolism to propionaldehyde, propionate and possibly 2-hydroxyglutarate. A number of alternative intermediary metabolites were ruled out. 2. Accumulation of propionaldehyde from 1-aminopropan-2-ol by intact cells occurred only during active growth, was transitory and was accompanied by morphological changes in the pseudomonad. 3. Enzymic and radioactive tracer evidence showed that 1-aminopropan-2-ol O-phosphate was the intermediate between amino alcohol and aldehyde. The operation of an inducibly formed ATP-amino alcohol phosphotransferase was established by measuring substrate disappearance, ADP formation and amino alcohol O-phosphate formation. This novel kinase had two activity peaks at about pH7 and 9. It acted on both l- and d-isomers of 1-aminopropan-2-ol, and also on l-threonine and ethanolamine, but had only low activity towards choline. The enzyme was partially purified by ion-exchange chromatography. 4. An amino alcohol O-phosphate phospho-lyase (deaminating) produced propionaldehyde from dl- and d-1-aminopropan-2-ol O-phosphate, and also formed acetaldehyde less rapidly from ethanolamine O-phosphate. It had optimum activity at about pH8 in Tris-HCl buffers. The enzyme was partially purified and evidence was obtained that a single enzyme was responsible for both activities. Apparent K(m) values for the substrates were determined. Activity was inhibited by dl-threonine O-phosphate, dl-serine O-phosphate, choline O-phosphate and P(i). Enzyme formation was induced by growth with either amino alcohol substrate. 5. Radioactive tracer experiments with dl-1-amino[3-(14)C]propan-2-ol confirmed the operation of the amino alcohol kinase and demonstrated coupling with the phospho-lyase enzyme in vitro to produce [(14)C]-propionaldehyde. 6. An aldehyde dehydrogenase, found in extracts of the pseudomonad after growth on 1-aminopropan-2-ol, was characterized and concluded to be responsible for propionaldehyde and acetaldehyde oxidation. The enzyme was inactive with methylglyoxal. 7. Propionate and acetate were concluded to be metabolized via propionyl-CoA and acetyl-CoA, and studies were made of a CoA ester synthase found in extracts. 8. Studies of a strain of Pseudomonas putida N.C.I.B. 10558 suggested that 1-aminopropan-2-ols were metabolized via their O-phosphates, propionaldehyde and propionate. Amino alcohol kinase activity was detected and extracts contained a phospho-lyase showing higher activity with the 1-aminopropan-2-ol O-phosphate than with ethanolamine O-phosphate.

Seawater biodegradation of alkanolamines used for CO2-capture from natural gas

“…The bacterial strain Pseudomonas sp. P6 was therefore grown on 1-aminopropan-2-ol (Jones and Turner, 1973) and acetate, and RNA extracted from cultures growing on both carbon-sources. After three separate mRNA enrichments 23S and 16S rRNA bands were still highly visible by gel electrophoresis (not shown).…”

Bacterial catabolism of threonine. Threonine degradation initiated by L-threonine-NAD+ oxidoreductase

“…Reaction mixtures contained 20,umol of Tris/HCI buffer (Trizma grade from Sigma Chemical Co., St. Louis, MO, U.S.A.), cell-free extract and 100lmol of L-threonine in a total volume of 1 ml. Reactions were terminated by the addition of an equal volume of aldehyde reagent (0.4% N-methylbenzothiazolone hydrazone in 0.1M-3,3-dimethylglutaric acid/NaOH buffer, pH4) and colours developed by the procedure described elsewhere (Jones & Turner, 1973). Assays were carried out at pH 8.5, at which all known bacterial L-threonine aldolases are active (Bell & Turner, 1973), and under a variety ofother conditions as indicated in the text.…”

The Biodegradation of Diethanolamine and Triethanolamine by a Yellow Gram-negative Rod

“…Isolation of a volatile aldehyde formed during growth. This was carried out in an apparatus similar to that described by Dagley & Gibson (1965) and Jones & Turner (1973). The method involved pumping, for 48 h, an air-stream through an otherwise sealed culture vessel at 30 "C and then through foam and condensation traps into two Dreschel bottles containing 2&dinitrophenylhydrazine (0.1 %, w/v, solution in 2 M-HCI).…”

“…Ethanolamine deaminase was assayed as described by Kaplan & Stadtman (1 97 l), ATP : ethanolarnine phosphotransferase (EC 2.7.1.82) by the first of the two methods used by Jones & Turner (1973) and ethanolamine-O-phosphate phospho-lyase (EC 4.2.99.7) by their spectrophotometric method. Aldehyde dehydrogenase (EC 1 .2.1.3) activity was followed at 340 nm in a mixture that contained (in a final volume of 3 ml) 100 pmol Tris buffer (pH 8.5), 2 pmol NAD+, 10 pmol glycolaldehyde or acetaldehyde and extract.…”