...er...I had forgotten that I made this node. I must say it's not very useful, so I'll give a short definition first.
Metabolism is the complex network of reactions that occur in the cell. These have traditionally been drawn as a large map (for E.coli, usually) or graph with substrates as nodes and enzymes as edges. Since these networks are fiendishly complex, they can be difficult to draw by hand. Automated layout is just as tricky, since the computational result is often tangled.
Amusingly, KEGG uses 60 japanese women, from skilled professions, to draw pathways by hand. that, is, using some sort of graphical editor, not with paintbrushes on silk...
This is incomplete...
G3P < -GAPDH- GAP
Pyr -LDH- > Lac