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Updated: Oct 8, 2026

Determination of the Glycogen Content in Cyanobacteria
Published on: July 17, 2017
Simultaneous occurrence of two different glyceraldehyde-3-phosphate dehydrogenases in heterocystous N(2)-fixing
F Valverde1, M L Peleato, M F Fillat
1Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Seville, Spain.
Abstract:
Enzyme activity determinations and Western and Northern blot analyses have shown the presence of two catalytically different glyceraldehyde-3-phosphate dehydrogenases (GAPDH) in both vegetative cells and heterocysts of several N(2)-fixing Anabaena strains: (a) the gap2-encoded NAD(P)-dependent GAPDH2 (EC 1.2.1.59), the enzyme involved in the photosynthetic carbon assimilation pathway, which is present at higher levels in vegetative cells, and (b) the gap3-encoded NAD-dependent GAPDH3 (EC 1.2.1.12), presumably involved in carbohydrate anabolism and catabolism, which is the predominant GAPDH in heterocysts. In contrast, the gap1-encoded GAPDH1, which is the other NAD-dependent cyanobacterial GAPDH, is virtually absent in both cell types. These findings are discussed in the context of carbon metabolism of heterocystous N(2)-fixing cyanobacteria.
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