ID   2.3.1.94
DE   6-deoxyerythronolide-B synthase.
AN   6-deoxyerythronolide B synthase.
AN   DEBS.
AN   deoxyerythronolide B synthase.
AN   erythronolide-condensing enzyme.
AN   erythronolide synthase.
CA   6 (S)-methylmalonyl-CoA + 12 H(+) + 6 NADPH + propanoyl-CoA =
CA   6-deoxyerythronolide B + 6 CO2 + 7 CoA + H2O + 6 NADP(+).
CC   -!- The product, 6-deoxyerythronolide B, contains a 14-membered lactone
CC       ring and is an intermediate in the biosynthesis of erythromycin
CC       antibiotics.
CC   -!- Biosynthesis of 6-deoxyerythronolide B requires 28 active sites that
CC       are precisely arranged along three large polypeptides, denoted DEBS1,
CC       -2 and -3.
CC   -!- The polyketide product is synthesized by the processive action of a
CC       loading didomain, six extension modules and a terminal thioesterase
CC       domain.
CC   -!- Each extension module contains a minimum of a ketosynthase (KS),
CC       an acyltransferase (AT) and an acyl-carrier protein (ACP).
CC   -!- The KS domain both accepts the growing polyketide chain from the
CC       previous module and catalyzes the subsequent decarboxylative
CC       condensation between this substrate and an ACP-bound methylmalonyl
CC       extender unit, introduce by the AT domain.
CC   -!- This combined effort gives rise to a new polyketide intermediate that
CC       has been extended by two carbon atoms.
DR   Q03131, ERYA1_SACER;  Q03132, ERYA2_SACER;  Q03133, ERYA3_SACER;
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