Pyruvate decarboxylase carbohydrate synthesis

A unique combmation of pyruvate decarboxylase and aldolase-catalyzed carbohydrate syntheses was recently developed by us. In the synthesis of sialic acid starting from iV- teetyl-D-mannosamine and pyruvic acid catalyzed by the sialic acid aldolase, the sqparation of the desired product, sialic acid, and the excessively used pyruvic acid has been a serious... 

Some acetogenic bacteria, which convert CO2 to acetic acid, form pyruvate for synthesis of carbohydrates, etc., by formation of formaldehyde and conversion of the latter to glycine by reversal of the PLP and lipoic acid-dependent glycine decarboxylase, a 4-protein system. The glycine is then converted to serine, pyruvate, oxaloacetate, etc. Propose a detailed pathway for this sequence. 

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