What is the precursor of proline in Krebs cycle?

Ans. is 'b' i.e., a-ketoglutarate * Proline is an alpha aminoacid with a pyrrolidine ring* It is a non polarimino acid with NH as one of its functional groups* It disrupts a helix* It is a nonessential amino acid and is synthesized from a non-essential aminoacid glutamate* Glutamate in the presence of g glutamate kinase gets converted to glutamate 5 phosphate, which in the presence of g glutamate dehydrogenase gets converted to y glutamate semialdehyde, g glutamate semialdehyde spontaneously cyclises to form y pyrroline carboxylate which in the presence of reductase forms proline.* Glutamate is formed from alpha ketoglutarate, an intermediate of citric acid cycle. Hence, the precursor of proline is a ketoglutarate of citric acid cycle* Proline on catabolism gives rise to glutamate and hence alphaketoglutarate and it gets into citric acid cycle to get burnt out as carbondioxide. If need arises, alpha ketoglutarate gets converted to oxaloacetate and through oxaloacetate it gets into gluconeogenesis and hence it is a glucogenicaminoacid.S.NONon essential/ semiessential aminoacidSource1AlaninePyruvate2Arginine (also from urea cycle) 3Proline 4HistidineaKetoglutarate5Glutamine 6Glutamate 7AsparagineOxaloacetate8Aspartate9Serine3 - Phosphoglycerate10GlycineSerine11Cysteine12TyrosinePhenylalanine