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. Author manuscript; available in PMC: 2010 Jun 15.
Published in final edited form as: Free Radic Biol Med. 2009 Mar 27;46(12):1626–1632. doi: 10.1016/j.freeradbiomed.2009.03.017

Table 1. Inhibition of nitric oxide synthases by cobalamins and cobinamides.

The effects of the indicated agents on the enzymatic activity of NOS1 and NOS2 were determined. Methyl-cobalamin and adenosylcobalamin were tested either having been exposed to light or not exposed to light. Results are displayed as the ED50 (μM).

Estimated ED50 (μM)
NOS1 NOS2 NOS3
Hydroxocobalamin 5.7 21.1 9.1
Cobinamide 15.0 50.0 43.0
Dicyanocobinamide 0.23 2.29 0.33
Cyanocobalamin 72.0 1620.0 519.0
Glutathionylcobalamin 9.6 29.0 41.0
Carboxy-PTIO 1360.0 1359.0 -
Methylcobalamin (no light) 576.0 231.0 -
Methylcobalamin (with light) 5.9 63.0 -
Adenosylcobalamin (no light) 498.0 2148.0 -
Adenosylcobalamin (with light) 6.4 60.0 -