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. Author manuscript; available in PMC: 2013 Jan 1.
Published in final edited form as: Biochem Pharmacol. 2011 Oct 14;83(1):149–163. doi: 10.1016/j.bcp.2011.10.007

Table 2.

Summary of the MS/MS fragmentation patterns of atRA and atRA-d5 metabolites formed by CYP26B1. The metabolites that are also oxidized to the same products when incubated separately with CYP26B1 are listed. The five most abundant fragments that were also ≥ 10 % abundance are listed.

Metabolite rt
(min)		 Parent m/z Fragment m/z
(% abundance)		 Formed from
4,16-(OH)2-RA 10.4 331 239 (86), 201 (31), 137 (31),
119 (41), 79 (10)		 4-OH-RA
(OH)2-RA 12.3 331 257 (12), 239 (100),
201 (25), 137 (13), 119 (32)		 4-OH-RA
4-oxo-16-OH-RA 12.3 329 255 (100), 171 (16),
137 (30), 135 (26), 119 (24)		 4-OH-RA and
4-oxo-RA
4,18-(OH)2-RA 13.7 331 269 (45), 251 (50), 177 (24),
149 (20), 137 (27)		 4-OH-RA and
18-OH-RA
oxo-OH-RA 14.2 329 269 (50), 267 (100),
131 (92), 119 (50), 97 (42)		 4-OH-RA and
18-OH-RA
4-OH-RA 17.8 315 253 (100), 151 (33),
119 (21), 79 (24)
4-oxo-RA 18.6 313 269 (100), 254 (83),
163 (41), 151 (19), 119 (67)		 4-OH-RA
16-OH-RA 19.0 315 241 (57), 119 (12)
18-OH-RA 19.5 315 271 (25), 255 (40), 253 (92),
237 (83), 137 (25)
atRA-d5 incubation
4,16-(OH)2-RA 10.4 335 243 (100), 204 (14),
141 (11), 119 (22)
(OH)2-RA 12.3 335 261 (13), 243 (100),
204 (24), 119 (30), 79 (14)
4,18-(OH)2-RA 13.6 334 272 (45), 258 (23),254 (22),
138 (27), 79 (23)
4-OH-RA 17.7 319 257 (100), 155 (11),
154 (14), 120 (13)
4-oxo-RA 18.5 316 272 (100), 257 (18),
254 (63), 165 (22), 120 (24)
16-OH-RA 18.9 320 246 (100), 120 (11), 119 (18)
18-OH-RA 19.5 319 275 (28), 257 (42), 241 (25),
240 (40), 239 (33)