Phylogenetic tree of PhcC and PhcD with known and putative GMC oxidoreductase family enzymes. The scale corresponds to a genetic distance of 0.06 substitutions per position. GMC oxidoreductase family enzymes include the following, with locus tags or GenBank accession numbers in parentheses: PhcC (SLG_09480) and PhcD (SLG_09500), DCA-C oxidases of Sphingobium sp. SYK-6; BetA_Ec, choline dehydrogenase of E. coli K-12 (P17444) (43); BetA_Cs, choline dehydrogenase of Chromohalobacter salexigens DSM 3043 (Q9L4K0) (54); BetA_Rm, choline dehydrogenase of Rhizobium meliloti 1021 (P54223) (55); AlkJ_Pp, alcohol dehydrogenase of Pseudomonas putida GPo1 (Q9WWW2) (48); PegA_St, polyethylene glycol dehydrogenase of Sphingopyxis terrae (Q93I49) (49); Pno_Ml, pyridoxine 4-oxidase of Microbacterium luteolum YK-1 (Q9AJD6) (56); BetA_Mm, 5-hydroxymethylfurfural oxidase of Methylovorus sp. MP688 (E4QP00) (57); Gox_An, glucose oxidase of Aspergillus niger NRLL-3 (P13006) (58); Gox_Pa, glucose oxidase of Penicillium amagasakiense (P81156) (46); P2ox_Pc, pyranose 2-oxidase of Phanerochaete chrysosporium BKM-F-1767 (Q6QWR1) (59); P2ox_Tv, pyranose 2-oxidase of Trametes versicolor (P79076) (60); P2ox_Pg, pyranose 2-oxidase of Phlebiopsis gigantea DSM 13218 (Q6UG02) (61); P2ox_Tm, pyranose 2-oxidase of Tricholoma matsutake (Q8J2V8) (62); ChoB_Bs, cholesterol oxidase of Brevibacterium sterolicum (P22637) (63); ChoA_Ss, cholesterol oxidase of Streptomyces sp. SA-COO (P12676) (64); ChoD_Mt, cholesterol oxidase of Mycobacterium tuberculosis H37Rv (P9WMV9) (65); Mox_Pa, methanol oxidase of Pichia angusta (P04841) (66); and Aod1_Cb, alcohol oxidase of Candida boidinii S2 (Q00922) (67). Putative GMC oxidoreductase family enzymes include the following: SLG_11400, SLG_12830, SLG_20170, and SLG_27980 of Sphingobium sp. SYK-6; WYH_02651, WYH_02653, and WYH_02869 of Altererythrobacter atlanticus 26DY36; TS85_05630 and TS85_05635 of Sphingomonas sp. WHSC-8; L288_14545 of Sphingobium quisquiliarum P25; NSU_1606 of Novosphingobium pentaromativorans US6-1; Caul_3245 of Caulobacter sp. K31; M529_19015 of Sphingobium ummariense RL-3; and YP76_13265 of Sphingobium chungbukense DJ77.