T. Suzuki et al., A NOVEL ENZYMATIC DEHALOGENATION OF (R)-3-CHLORO-1,2-PROPANEDIOL IN ALCALIGENES SP DS-S-7G, Applied microbiology and biotechnology, 42(2-3), 1994, pp. 270-279
The mechanism of the novel enzymatic dehalogenating action of (R)-3-ch
loro-1,2-propanediol [monochlorohydrin (MCH)] was investigated. The (R
)-MCH-dechlorinating enzyme system of Alcaligenes sp. DS-S-7G, which s
tereoselectively assimilated (R)MCH from the racemate, was composed of
two components (Enzyme 1 and Enzyme 2). Enzyme 1 was a flavoprotein w
ith a relative molecular mass (M(r)) of 70,000 and was composed of two
kinds of polypeptides (58,000 and 16,000). The enzyme exhibited activ
ity for converting (R)-MCH to hydroxyacetone with the liberation of ch
loride ions under aerobic conditions. On the other hand, Enzyme 2 with
an M(r) of 86,000, which was also composed of two kinds of polypeptid
es (33,000 and 53,000), showed no dechlorinating activity for (R)MCH.
However, in the presence of NAD(+), when Enzyme 1 was conjugated with
Enzyme 2 in the (R)MCH-dechlorinating reaction, the co-operative dechl
orinating activity was four to five times higher than that by Enzyme 1
alone. (R)-MCH was finally degraded to acetic acid and formic acid by
the joint action of the two enzymes. These facts indicate that (R)-MC
H is oxidatively dechlorinated by the two enzymes in the presence of N
AD(+) in Alcaligenes sp. DS-S-7G.