Properties and regional distribution of ocular aldehyde dehydrogenase in the rat

The rat eye possesses cytoplasmic aldehyde dehydrogenase (ALDH) activity. The enzyme is present in whole eye, in ocular fluids and is distributed in specific ocular regions. The specific activity of cornea ALDH was the highest among 6 regions studied. The ciliary body and iris combined displayed second largest activity followed by even distribution of ALDH in the retina, the sclera and the surrounding connective tissue. The cloroid and lens did not show measurable ALDH activity. The kinetics property of cornea-ALDH indicate high Vmax. In vitro addition of equal protein concentration of individual ocular regional preparations to the cornea decreased specific activity of cornea-ALDH suggesting of protein interaction and/or substrate competition phenomenon. Short-term oral administration of Vitamin A resulted in statistically insignificant increase of whole ocular tissue ALDH from controls as contrasted with inhibition of ALDH in the ocular fluid by similar short-term oral administration of disulfiram.