Figure 11 of
Nickerson, Mol Vis 4:33, 1998.
Figure 11. All-trans-retinol decomposition
11-cis-retinol decomposes rapidly in aqueous buffers without the presence of antioxidants or intact bovine IRBP . Decomposition of all-trans-retinol exhibits similar properties  with or without bovine IRBP. The individual human repeats exhibit similar protective effects as shown in the figure. 8 µM retinol and 16 µM of each repeat (or BSA) was added to a cuvette and the degradation of all-trans-retinol was monitored by the decrease in absorbance at 330 nm. Whereas retinol in buffer (aqua circles) rapidly deteriorates at 25 °C, EcR1 (red triangles), EcR3 (blue diamonds), EcR4 (magenta hexagons), and BSA (black squares) offer roughly the same degree of protection from breakdown. EcR2 (green triangles) provides a slightly higher degree of protection. In this experiment the buffer used was Hank's balanced salt solution lacking calcium and magnesium.