Pterin deaminase and

Enzymatic deamination of the naturally occurring pteridin-6-yl acyclo C-nucleosides biopterin (615), dictypterin (616), o-neopterin (618), and d-monapterin (620) with pterin deaminase from the slime mold Dictyostelium discoideum caused their conversion to the corresponding lumazin-6-yl 2,4-dioxopyrazino[2,3-d]pyrimidin-6-yl acyclo C-nucleosides biolumazine (672), dictyolumazine (673), D-neolumazine (674), and D-monalumazine (675), respectively (94MI2) (Scheme 174). 

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