Open AccessThe biosynthesis pathway of di‐ myo ‐inositol‐1,1′‐phosphate in Pyrococcus woesei
Author(s) -
Scholz Stefan,
Wolff Stefan,
Hensel Reinhard
Publication year - 1998
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1998.tb13252.x
Subject(s) - inositol , phosphate , chemistry , biochemistry , inositol phosphate , dephosphorylation , biosynthesis , nad+ kinase , cofactor , sugar phosphates , enzyme , stereochemistry , phosphatase , receptor
From in vitro experiments with dialyzed cell‐free extracts of the hyperthermophilic Archaeum Pyrococcus woesei , the biosynthetic pathway of di‐ myo ‐inositol‐1,1′‐phosphate was deduced. Starting from glucose 6‐phosphate, the synthesis proceeds in two steps with l ‐ myo ‐inositol 1‐phosphate as intermediate. (1) Interconversion of glucose 6‐phosphate to inositol 1‐phosphate was observed without adding cofactors, such as nucleoside triphosphates or pyridine dinucleotides suggesting that the first enzyme reaction corresponds to the NAD + ‐dependent inositol 1‐phosphate synthase reaction as already described for eukaryal systems, but differing from the latter by a stronger pyridine dinucleotide binding rendering the enzyme virtually independent from external NAD + . (2) In a second step, two l ‐ myo ‐inositol 1‐phosphates are coupled under the expense of NTP to yield di‐ myo ‐inositol‐1,1′‐phosphate. The coupling of two l ‐ myo ‐inositol 1‐phosphates without preceding dephosphorylation of one of both by a phosphorylase as proposed for the di‐ myo ‐inositol‐1,1′‐phosphate synthesis in Methanococcus igneus (Chen, L. and Roberts, M. (1998) Appl. Environ. Microbiol. 64, 2609–2615) is supported by labeling experiments which resulted only in a labeled product with l ‐ myo [U‐ 14 C]inositol 1‐phosphate, but not with radiolabeled l ‐ myo ‐[U‐ 14 C]inositol and non‐labeled l ‐ myo ‐inositol 1‐phosphate.