The Citric Acid Cycle

Mary Gearing

Problems with this pathway

• Where does the oxaloacetate come from?

• How do we convert oxaloacetate to malate?

Where in the world is 1.1.1.37?

• BLAST our genome against 1.1.1.37 (H. salinarium)

Mistaken identity???

Different BLAST result

Can our organism convert pyruvate to oxaloacetate? (Enzyme 6.4.1.1)

PyruvatePyruvate

OxaloacetateOxaloacetate

6.4.1.16.4.1.1

BLASTing our genome

Both correspond to EC number 2.3.3.13 (2-isopropylmalate synthase)

So where does the oxaloacetate come from anyway?

• Aspartate metabolism

• Glycoxylate metabolism

L-aspartateL-aspartate OxaloacetateOxaloacetate2.6.1.12.6.1.1

Unanswered Questions

Oxaloacetate/malate conversion

Pyruvate/oxaloacetate conversion

We still don’t know if these processes occur in H. utahensis.