Sandbox Reserved 325: Difference between revisions

The gene Rv1885c from ''Mycobacteriam tuberculosis'' encodes for a non-functional chorismate mutase (*MtCM)<ref name="pizza" />.  This non-functional mutase has a 33-amino-acid cleavable sequence <ref name="pizza" />.  It is a vital enzyme in the shikimate pathway, which allows for the synthesis of tryptophan, tyrosinem and phenylalanine <ref name="pizza" />.  This protein acts at the first branch point of the shikimate pathway, making it a regulating step in this pathway<ref name="CMW2"> PMID:PMC55368 </ref>.  Chorismate mutase provides a 2x10⁶ fold increase in the rate of reacrion in comparision to the uncatalyzed reaction <ref > P.D. Lyne, A.J. Mulholland, W.G. Richards. Insights into chorismate mutase catalysis from a combined qm/mm simulation of the enzyme reaction. Journal of the American Chemistry Society. 1995 117(45):11345-11350</ref>.  Chorismate mutase only occurs in bacteria, higher plants, and fungi, due to the fact that the shikimate pathway is only found in these organisms <ref name="strat" />.  In ''Escherichia coli'', chorismate mutase has a periplasmic destination<ref name="pizza" />.  In ''M. tuberculosis'' there is in abscence of a periplasmic compartment for chorismate mutase, so it secretes into the culture filtrate of ''M. tuberculosis''<ref name="pizza" />.  It is believed that a pseudoperiplasmic space might exist in ''M. tuberculosis''<ref name="pizza" />. Rv1885c is synthesized along with the 33-amino-acid terminal sequence, which when expressed with ''Escherichia coli'', is cleaved off the mature protein<ref name="pizza"  />.  Chorismate mutase is the only example of an enzyme catalyzing a percyclic reaction <ref name="strat"> PMID:10960481 </ref>

proteins of E. coli, Mtb chorismate mutase

Chorismate mutase is an essential enzyme in the shikimate pathway <ref name="pizza"> PMID:17146044 </ref>.  This pathway allows for the biosynthesis of aromatic amino acids tryptophan, tyrosine, and phenylalanine <ref name="pizza" />.  The production of tyrosine and phenylalanine is achieved by what is called a Claisen arrangement. first converting chorismate to prephenate.  Prephenate then reacts with prephenate dehydratase and prephenate dehydrogenase which forms phenylpyruvate and hydroxyphenylpyruvate.  After this occursm aminotransferase converts hydroxy-phenylpyruvate and phenylpyruvate to phenylalanine and tyrosine.  Chorismate mutase provides a 2x10⁶ fold increase in the rate of reaction, in comparison to the uncatalyzed reaction <ref > P.D. Lyne, A.J. Mulholland, W.G. Richards. Insights into chorismate mutase catalysis from a combined qm/mm simulation of the enzyme reaction. Journal of the American Chemistry Society. 1995 117(45):11345-11350</ref>.  It is the only example of an enzyme catalyzing a percyclic reaction <ref name="strat"> PMID:10960481 </ref>