Front Matter

(Tina Sui) #1
A scheme of the binding site is shown in Figure 3, with the amino acids Arg 47 and

Tyr 51 (which are responsible for the substrate fixation) and Phe 87 (which influences

the regioselectivity of the fatty acid hydroxylation) each being highlighted. The

substrate profile of P450 BM-3 is summarized in Table 2.

18.4 Fatty Acid-hydroxylating P450s Monooxygenases 401

Table 2.Substrate profile of P450 BM-3 wild-type and mutants.


Substrates Fatty acid
chain-length


P450 Km Kcat/Km References

[lM] [*10^5 M^1 *s^1 ]

Saturated FA WT 136, 7, 1.4 1.9, 82, 600 Oliver et al.,
1997a
C 12 ,C 14 ,C 16 R47E 2000, 18, 4 0.15, 3.9, 30 Oliver et al.,
1997a
C 12 F87A 167 1.5 Oliver et al.,
1997b
Polyunsaturated FA WT n.m. n.m. Capdevila et al.,
1996
C20:3,C20:4,C20:5 F87V n.m. n.m. Graham-Loren-
ce, 1997
x-Oxo-FA C 12 ,C 14 ,C 16 ,C 18 WT n.m. n.m. Davis et al., 1996
p-Nitrophenoxy-FA WT n.m. n.m. Schwaneberg et
al., 1999a
C 8 ,C 10 ,C 11 ,
C 12 ,C 15


F87A n.m. n.m. Schwaneberg et
al., 1999a
Trialkylmethylammo-
nium


WT 782, 87, 5 200, 25, 2 Oliver et al.,
1997a
C 12 ,C 14 ,C 16 R47E 95, 23, 9 23, 6.6, 0.22 Oliver et al.,
1997a

FA, fatty acids; n.m., not measured


Figure 3. Model of the heme-domain of P450 BM-3 with boundp-nitrophenoxy dodecanoic acid (12-
pNCA). Amino acids involved in substrate binding (Arg 47 ,Tyr 51 ) and regioselectivity (Phe 87 ) are high-
lighted.

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