┌─────────────────────────────────────────────────────── Escherichia coli IAI39 (1)  
┤                                                                ┌─ Escherichia coli K12 (28)  
│                                       ┌────────────────────────┴──── Escherichia coli 53638 (1)  
└───────────────────────────────────────┤┌──── Escherichia coli TA143   
                                        └┤   ┌──── Escherichia coli ED1a (1)  
                                         │   │     ┌──── Escherichia coli SE15   
                                         └───┤ ┌───┴─ Escherichia coli UM146 (2)  
                                             │┌┴─────── Escherichia coli B354 (1)  
                                             └┤ ┌─ Escherichia coli 2362-75 (19)  
                                              └┬┴──── Escherichia coli M605   
                                               └┬──── Escherichia coli SMS-3-5   
                                                └──── Escherichia coli 83972 (1)  
  

  
Xanthosine phosphorylase (EC 2.4.2.1)
 (12)