Retinyl ester hydrolase and the visual cycle in the chicken eye

J. J. Bustamante, S. Ziari, R. D. Ramirez, A. T C Tsin

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The ability of chicken retina and retinal pigment epithelium (RPE) membrane to hydrolyze vitamin A esters ([9,10-3H]all-trans- and 11-cis- retinyl palmitate) was studied. Hydrolytic activity within the retina was optimal at acidic pH of 5.0, whereas in the RPE significant hydrolytic activity was exhibited over a broad range of hydrogen ion concentrations. The highest rate of hydrolysis was associated with the all-trans-isomer and located within retina and RPE membranes [the apparent maximal velocity (V(max)) and Michaelis-Menten constant (K(m)) were 770 pmol · min · -1 · mg-1 and 45 μM and 300 pmol · min · -1 · mg-1 and 3.6 μM, respectively]. Retinyl ester hydrolase activities for 11-cis-retinyl palmitate in the retina and RPE were correspondingly lower (apparent V(max) of 204 pmol · min · -1 · mg-1 and K(m) of 18.5 μM in the retina; apparent V(max) of 131 pmol · min · -1 · mg-1 and K(m) of 4 μM in the RPE). Together with results from other laboratories, results from the present study suggest that chicken retina contains important enzymes to complete the visual cycle.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume269
Issue number6 38-6
StatePublished - Dec 1 1995

Fingerprint

hydrolases
retina
Retinal Pigment Epithelium
Retina
Chickens
eyes
esters
chickens
epithelium
pigments
retinyl palmitate
Membranes
Vitamin A
vitamin A
retinyl esterase
Esters
Hydrolysis
hydrolysis
Enzymes
enzymes

Keywords

  • enzymes
  • retina
  • retinyl pigment epithelium
  • vitamin A

ASJC Scopus subject areas

  • Physiology
  • Agricultural and Biological Sciences(all)

Cite this

Retinyl ester hydrolase and the visual cycle in the chicken eye. / Bustamante, J. J.; Ziari, S.; Ramirez, R. D.; Tsin, A. T C.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 269, No. 6 38-6, 01.12.1995.

Research output: Contribution to journalArticle

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