synthase

Examples of synthase in the following topics:

• F10 ATP Synthase

  • The overall reaction sequence is: ATP synthase + ADP + Pi → ATP Synthase + ATP
  • Located within the mitochondria, ATP synthase consists of 2 regions: the FO portion is within the membrane and the F1 portion of the ATP synthase is above the membrane, inside the matrix of the mitochondria .
  • Oligomycin, an antibiotic, is able to inhibit the FO unit of ATP synthase.
  • E. coli ATP synthase is the simplest known form of ATP synthase, with 8 different subunit types.
  • Discuss the structure and function of ATP synthase, including the F1 and FO components

• Purine and Pyrimidine Synthesis

  • UDP can also be converted to CTP by CTP synthase cytidine 5'triphosphate (CTP)using glutamine and ATP.The first three enzymes are all coded by the same gene in Metazoa (CAD).
  • CTP synthase (or CTP synthetase) is an enzyme involved in pyrimidine biosynthesis.
  • CTP synthase is activated by GTP, a purine.
  • CTP synthase is inhibited by reversible by CTP and irreversible for example by the glutamine analogon DON.
  • The following human genes encode proteins that possess CTP synthase activity:

• Polyketide Antibiotics

  • The polyketide chains produced by a minimal polyketide synthase are often further derivitized and modified into bioactive natural products.
  • Polyketides are synthesized by one or more specialized and highly complex polyketide synthase (PKS) enzymes.

• Respiration and Proton Motive Force

  • They are able to do this with the help of the solar-driven enzyme bacteriorhodopsin, which is used to drive the molecular motor enzyme ATP synthase to make the necessary conformational changes required to synthesize ATP.
  • By running ATP synthase in reverse, proton gradients are also made by bacteria and are used to drive flagella.
  • The F1FO ATP synthase is a reversible enzyme.
  • In respiring bacteria under physiological conditions, ATP synthase, in general, runs in the opposite direction.

• Proton Reduction

  • In respiring bacteria under physiological conditions, ATP synthase, in general, runs in the opposite direction, creating ATP while using the proton motive force created by the electron transport chain as a source of energy.
  • The same process takes place in the mitochondria, where ATP synthase is located in the inner mitochondrial membrane, so that F1 part sticks into the mitochondrial matrix where ATP synthesis takes place.
  • A proton motive force or pmf drives protons down the gradient (across the membrane) through the proton channel of ATP synthase.

• The Acetyl-CoA Pathway

  • The two major enzymes involved in these processes are carbon monoxide dehydrogenase and acetyl CoA synthase complex.
  • The acetyl-CoA synthase complex is responsible for this reaction.
  • The carbon monoxide dehydrogenase allows organisms to use carbon dioxide as a source of carbon and carbon monoxide as a source of energy.The carbon monoxide dehydrogenase can also form a complex with the acetyl-CoA synthase complex which is key in the acetyl-CoA pathway.

• Citric Acid and Other Organic Compounds

  • It is produced from acetyl coenzyme A and oxaloacetate in the presence of the enzyme citrate synthase.

• Photoautotrophs and Photoheterotrophs

  • All phototrophs either use electron transport chain or direct proton pumping to establish an electro-chemical gradient utilized by ATP synthase to provide molecular energy for the cell.

• Bacterial Polyesters

  • PHA synthases are the key enzymes of PHA biosynthesis.
  • The two classes of PHA synthases differ in the specific use of hydroxyfattyacids of short or medium chain length.

• Lipid Biosynthesis

  • Fatty acids are made by fatty acid synthases that polymerize and then reduce acetyl-CoA units.
  • The enzymes of fatty acid biosynthesis are divided into two groups, in animals and fungi all these fatty acid synthase reactions are carried out by a single multifunctional protein, while in plant plastids and bacteria separate enzymes perform each step in the pathway.