ID 1.14.99.64 DE zeaxanthin 4-ketolase. CA (1) 2 AH2 + all-trans-zeaxanthin + 2 O2 = 2 A + all-trans-adonixanthin + CA 3 H2O. CA (2) 2 AH2 + all-trans-adonixanthin + 2 O2 = 2 A + all-trans-(3S,3'S)- CA astaxanthin + 3 H2O. CC -!- The enzyme has a similar activity to that of EC 1.14.99.63, CC but unlike that enzyme is able to also act on zeaxanthin. DR Q4VKB4, BKT_CHLRE ; //