BIOLOGY 2D03 Lecture Notes - Mitochondrial Matrix, Transesterification, Lipoic Acid
28 Jan 2013
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Variety of metabolic fates depending upon cell type and metabolic state. Pyruvate lactate (cori cycle) cat. by ldh. 5 isozymes, vary depending upon tissue type varying affinities for lactate and pyruvate heart: ldh1 high km (low affinity) for pyruvate low vmax for pyruvate lactate inhibted by pyruvate. **favors pyruvate for use in tca cycle** muscle: ldh5 low km (high affinity) for pyruvate high vmax for pyruvate lactate. **favors lactic acid for glycolysis** pyruvate reduced (to lactate) Nadh oxidized (to nad) glycolysis can continue. Cori cycle: pyruvate reduced in muscle lactate trans. to liver and is reconverted to pyruvate for gluconeogenesis new glucose is sent to muscle again. **very similar to cori cycle, but involves generating ammonia** Pyruvate carboxylase involved in first step of gluconeogenesis adds co2 to pyruvate, generating oxaloacetate enzyme uses biotin, atp. Malic enzyme adds co2 and reduces pyruvate malate (reverse direction is more common, as it makes pyruvate and reduces nadp)
