98
P. K. STUMPF AND G. A. BARBER
B. AEROBIC BACTERIA
Enzymes concerned with fatty acid oxidation are primarily constitutive, since cells not previously in contact with fatty acid substrates show
a high level of metabolism (68). Some strains of Serratia marcescens
(Alphin) and Bacillus brevis suggest formation of adaptive enzymes because of the lag period in the oxidation of Ci 8 acid by the organism
grown on glucose and the elimination of the lag when the organism is
grown in a caproate medium. Resting cell suspensions of several strains
of Pseudomonas, E. coli, B. brevis, B. firmis, B. subtilis, and B. megatherium readily oxidized capric and pelargonic acids.
Among the aerobic and facultative bacteria studied, ß-oxidation of
fatty acids to active acetate fragments again appears to be the principle mechanism of their degradation.
In an investigation of Mycobacterium tuberculosis, Iida (69) found
that saturated fatty acids with even-numbered straight carbon chains
are oxidized by constitutive enzymes, and the acids with odd-numbered
straight chains by adaptive enzymes. By paper chromatography he
demonstrated that caproate (C 6 ) was an oxidation product of caprylate
(C 8 ) supporting the concept of ^-oxidation.
More direct evidence was provided by use of cell-free extracts of
Pseudomonas fluorescens (70). These extracts catalyzed the formation
of acetate from decanoate with the uptake of 1 pinole of 0 2 per ^mole
of substrate. Acetyl-S-CoA participation was inferred from the formation
of an acetyl hydroxamate upon incubation of the reaction mixtures with
hydroxylamine. By submitting the crude extract to an anion exchange
resin a requirement for the cofactors ATP, CoA, and Mg
2+ was demonstrated.
Murray and Dawes (71) established that fresh and freeze-dried
cells of Sarcina lutea oxidize C 2 , C 4 , C 5 , C G , C 8 , and C i0 fatty acids.
Specific enzymes shown to be active in cell-free extracts included acetoCoA kinase, butyryl dehydrogenase, and acyl dehydrogenase.
The existence of the ß-hydroxy intermediate in fatty acid oxidation
by aerobic bacteria was demonstrated in Nocardia opaca, a soil Actinomycete (72). Incubation of the cells with the substrate y-(3-chlorophenoxy)-butyric acid gave the corresponding acetic acid but much
larger quantities of the ß-hydroxybutyric acid derivative.
Additional evidence for the general nature of these oxidative pathways was provided by a study of a species of Vibrio (73). With cellfree extracts of that organism octanoate is oxidized by molecular oxygen
with an accumulation of acetic acid. DPN, CoA, and Mg
2+ are required
P. K. STUMPF AND G. A. BARBER
B. AEROBIC BACTERIA
Enzymes concerned with fatty acid oxidation are primarily constitutive, since cells not previously in contact with fatty acid substrates show
a high level of metabolism (68). Some strains of Serratia marcescens
(Alphin) and Bacillus brevis suggest formation of adaptive enzymes because of the lag period in the oxidation of Ci 8 acid by the organism
grown on glucose and the elimination of the lag when the organism is
grown in a caproate medium. Resting cell suspensions of several strains
of Pseudomonas, E. coli, B. brevis, B. firmis, B. subtilis, and B. megatherium readily oxidized capric and pelargonic acids.
Among the aerobic and facultative bacteria studied, ß-oxidation of
fatty acids to active acetate fragments again appears to be the principle mechanism of their degradation.
In an investigation of Mycobacterium tuberculosis, Iida (69) found
that saturated fatty acids with even-numbered straight carbon chains
are oxidized by constitutive enzymes, and the acids with odd-numbered
straight chains by adaptive enzymes. By paper chromatography he
demonstrated that caproate (C 6 ) was an oxidation product of caprylate
(C 8 ) supporting the concept of ^-oxidation.
More direct evidence was provided by use of cell-free extracts of
Pseudomonas fluorescens (70). These extracts catalyzed the formation
of acetate from decanoate with the uptake of 1 pinole of 0 2 per ^mole
of substrate. Acetyl-S-CoA participation was inferred from the formation
of an acetyl hydroxamate upon incubation of the reaction mixtures with
hydroxylamine. By submitting the crude extract to an anion exchange
resin a requirement for the cofactors ATP, CoA, and Mg
2+ was demonstrated.
Murray and Dawes (71) established that fresh and freeze-dried
cells of Sarcina lutea oxidize C 2 , C 4 , C 5 , C G , C 8 , and C i0 fatty acids.
Specific enzymes shown to be active in cell-free extracts included acetoCoA kinase, butyryl dehydrogenase, and acyl dehydrogenase.
The existence of the ß-hydroxy intermediate in fatty acid oxidation
by aerobic bacteria was demonstrated in Nocardia opaca, a soil Actinomycete (72). Incubation of the cells with the substrate y-(3-chlorophenoxy)-butyric acid gave the corresponding acetic acid but much
larger quantities of the ß-hydroxybutyric acid derivative.
Additional evidence for the general nature of these oxidative pathways was provided by a study of a species of Vibrio (73). With cellfree extracts of that organism octanoate is oxidized by molecular oxygen
with an accumulation of acetic acid. DPN, CoA, and Mg
2+ are required