E. coli has three operons encoding for three distinct cytochrome oxidase enzymes – cytochrome bo oxidase, cytochrome bd-1 oxidase and cytochrome bd-2 oxidase.

    1. Give the subunit composition for each of the cytochrome oxidases.

 

 

    1. How and which transcription factor(s) regulate expression of cytochrome bo oxidase and cytochrome bd-1 oxidase? What environmental factor(s) regulate gene expression?

 

 

    1. Name two substrates that can serve as electron donors to the cytochrome oxidases via the quinone pool? Name the enzymes that carry out the oxidation reactions.

 

 

  1. You decide to compare and contrast two electron transport chains both initiating from NDH-1.  The electron transport chains differ in their terminal oxidase using either cytochrome booxidase or cytochrome bd-1 oxidase. Describe the similarities and differences you find.  Explain why one creates more ATP.