中文摘要：

Phosphohexomutases 催化在 hexose-6-phosphate 和 hexose-1-phosphate 之间的互变现象并且在多糖合成起重要作用。在 Synechocystis sp。PCC 6803， sll0726 被预言编码 PGM (phosphoglucomutase ) ， slr1334 被预言编码 PGM/PMM (phosphomannomutase ) bifunction 酶。与野类型相比， sll0726 空的异种显示出 3.4% PGM 活动但是 45%69% 肝糖内容。slr1334 的下面规定，必要基因，由使用铜，调整倡导者进一步减少了在 sll0726::Kmr P petE -slr1334 的 PGM 活动两倍异种到 0.3% 野类型水平。然而，肝糖内容进一步没在平行被减少。在 vitro， recombinant Sll0726 或 Slr1334 显示出预言的酶活动。我们的结果显示那一相对，肝糖的高水平能与 PGM 的底层在 Synechocystis 异种被维持活动。在 cyanobacterium 的高 PGM 活动可以为肝糖的周转或另外的多糖或 oligosaccharides 的合成被要求。

英文摘要：

Phosphohexomutases catalyze the interconversion between hexose-6-phosphate and hexose-l-phosphate and play important roles in polysaccharide synthesis. In Synechocystis sp. PCC 6803, sl10726 is predicted to encode PGM （phosphoglucomutase）, slr1334 is predicted to encode a PGM/PMM （phosphomannomutase） bifunction enzyme. In comparison to the wild type, a sllO726-null mutant showed 3.4% PGM activity but 45%-69% glycogen content. Down-regulation of slr1334, an essential gene, by using a copper regulated promoter further decreased the PGM activity in the sllO726：：Kmr PpetE-slr1334 double mutant to 0.3% of the wild type level. However, the glycogen content was not further decreased in parallel. In vitro, recombinant Sl10726 or S1r1334 showed predicted enzyme activities. Our results indicate that a relatively high level of glycogen can be maintained in Synechocystis mutants with low levels of PGM activity. The high PGM activity in the cyanobacterium may be required for turnover of glycogen or synthesis of other polysaccharides or oligosaccharides.