Three major types of insect herbivores

Phloem feeders, such as aphids and whiteflies, cause little damage to the epidermis and mesophyll cells. Phloem feeders insert their narrow stylet, which is an elongated mouthpart, into the phloem sieve tubes of leaves and stems. 

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The liver PK isozyme (L form) is regulated by glucagon

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Pyruvate Carboxylase

a mitochondrial enzyme that requires the coenzyme biotin, converts the pyruvate to oxaloacetate

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The oxaloacetate is converted to PEP by phosphoenolpyruvate carboxykinase. This Mg2+ dependent reaction requires GTP as the phosphoryl group donor.

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Transketolase requires the cofactor thiamine pyrophosphate (TPP)

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Acetyl-CoA and NADH are potent allosteric inhibitors of the enzyme. 

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Acetyl-CoA inhibits the transacetylase component whereas NADH inhibits the dihydrolipoyl dehydrogenase component.