Suggested Reaction 1.1.1.-

Left

(5Z,13E)-(15S)-9alpha,15-Dihydroxy-11-oxoprosta-5,13-dienoate
+NAD+

Right

(5Z,13E)-9alpha-Hydroxy-11,15-dioxoprosta-5,13-dienoate
+NADH
+H+

[BiSSCat | GREP ]