cycle occurs in glyoxysomes. glyoxalate cycle

1. GLYOXLATE CYCLE
 Cyclic pathway for the conversion of fats into
carbohydrates.
 Plants and microorganisms carry out this cycle.
 Occurs in glyoxisomes.
 Anabolic varient of citric acid cycle.

2. STEPS OF CYCLE
 Acetyl CoA produced from fatty acid oxidation
condenses with oxaloacetate to give citrate.
 The enzyme involved is Citrate synthase.
 Citrate is then converted into isocitrate by the action of
enzyme Aconitase.
 At this stage isocitrate bypasses the citric acid cycle and
cleaved by isocitrate lyase to succinate and glyoxalate.

3. Conversion of isocitrate to
glyoxalate and succinate

4. STEPS….
 Another molecule of acetyl CoA combines with
glyoxalate to form malate.
 This reaction is catalyzed by enzyme Malate synthase.
 Malate enters citric acid cycle.

5. Formation of malate

6. STEPS…
 Succinate formed is converted into malate .
 Malate is then converted into oxaloacetate by enzyme
called Malate dehydrogenase.
 Oxaloacetate is the pecursor of gluconeogenesis.
 It is 1st converted into phosphoenolpyruvate by enzyme
PEP Carboxykinase and thus to glucose by
gluconeogenesis.

7. Cycle