Biochemical studies on 2-deoxy-scyllo-inosose - Part VII - Substrate specificity of 2-deoxy-scyllo-inosose synthase, the starter enzyme for 2-deoxystreptamine biosynthesis, toward deoxyglucose-6-phosphates and proposed mechanism
N. Iwase et al., Biochemical studies on 2-deoxy-scyllo-inosose - Part VII - Substrate specificity of 2-deoxy-scyllo-inosose synthase, the starter enzyme for 2-deoxystreptamine biosynthesis, toward deoxyglucose-6-phosphates and proposed mechanism, BIOS BIOT B, 62(12), 1998, pp. 2396-2407
A crucial enzyme in the biosynthesis of the 2-deoxystreptamine aglycon of c
linically important aminocyclitol antibiotics is 2-deoxy-scyllo-inosose syn
thase (DOIS), which. is responsible for the initial carbocycle formation of
2-deoxy-scyllo-inosose (1) from D-glucose-6-phosphate (G-6-P) (2). To get
more insight into the mechanism and substrate specificity, deoxy-D-glucose-
6-phosphates (deoxy-G-6-P) were chemically synthesized and subjected to the
reaction with DOIS. The enzyme appeared to use 2-deoxy- and 3-deoxy-G-6-P
as substrates, both of which were converted into the corresponding dideoxy-
scyllo-inosose products, but 4-deoxy-G-6-P failed in cyclization by DOIS. T
hese results clearly support the proposed reaction mechanism involving the
initial oxidation at C-4 of the G-6-P substrate. Another implication is the
potential use of DOIS for the preparation of useful dideoxyinososes.