Characterization of Esterases Involved in the Hydrolysis of Dipivefrin Hydrochloride
- 1 January 1993
- journal article
- research article
- Published by S. Karger AG in Ophthalmic Research
- Vol. 25 (1) , 46-51
- https://doi.org/10.1159/000267220
Abstract
We characterized the interaction of the prodrug dipivefrin hydrochloride (DPE) with esterase activity in the rabbit cornea. The esterases which were identified included: (1) cholinesterase, (2) acetylcholinesterase, (3) a mixture containing car-boxylesterase, acetylesterase and arylesterase, and (4) a nonspecific esterase. DPE suppressed all of their activities as well as that of the mixture containing carboxylesterase, acetylesterase and arylesterase, and a nonspecific esterase. However, its effect on cholinesterase was larger than on any of the other activities, suggesting that DPE is a better substrate for cholinesterase than for any of the other esterases. These measurements along with those of substrate-dependent inhibition of 14C-DPE hydrolysis indicated that the DPE-esterase interaction was competitive based on changes in the apparent Km values which were extracted from Lineweaver-Burk plots of esterase activity. The substrate for cholinesterase competed with DPE most strongly among substrates. These results seem to suggest that DPE is hydrolyzed by various corneal esterases, mainly cholinesterase.Keywords
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