Palmitoyl Transferase Activity of Lecithin Retinol Acyl Transferase
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- 作者：Linlong Xue ; Wan Jin Jahng ; Deviprasad Gollapalli ; Robert R. Rando
- 刊名：Biochemistry
- 出版年：2006
- 出版时间：September 5, 2006
- 年：2006
- 卷：45
- 期：35
- 页码：10710 - 10718
- 全文大小：290K
- 年卷期：v.45,no.35(September 5, 2006)
- ISSN：1520-4995
文摘
Lecithin retinol acyl transferase (LRAT) has the essential role of catalyzing the transfer of anacyl group from the sn-1 position of lecithin to vitamin A to generate all-trans-retinyl esters (tREs). Invitro studies had shown previously that LRAT also can exchange palmitoyl groups between RPE65, atRE binding protein essential for vision, and tREs. This exchange is likely to be of regulatory significancein the operation of the visual cycle. In the current study, the substrate specificity of LRAT is exploredwith palmitoylated amino acids and dipeptides as RPE65 surrogates. Both O- and S-substituted palmitoylatedanalogues are excellent substrates for tLRAT, a readily expressed and readily purified form of LRAT.Using vitamin A as the palmitoyl acceptor, tREs are readily formed. The cognate of these reactions occursin crude retinal pigment epithelial (RPE) membranes as well. RPE membranes containing LRAT transferpalmitoyl groups from radiolabeled [1-14C]-L-
-dipalmitoyl diphosphatidylcholine (DP*PC) to RPE65.Palmitoyl transfer is abolished by preincubation with a specific LRAT antagonist both in membranes andwith purified tLRAT. These experiments are consistent with an expanded role for LRAT function as aprotein palmitoyl transferase.
-dipalmitoyl diphosphatidylcholine (DP*PC) to RPE65.Palmitoyl transfer is abolished by preincubation with a specific LRAT antagonist both in membranes andwith purified tLRAT. These experiments are consistent with an expanded role for LRAT function as aprotein palmitoyl transferase.