HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Burdette, R. A. Articles by Quinn, D. M. Search for Related Content PubMed PubMed Citation Articles by Burdette, R. A. Articles by Quinn, D. M. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 261, Issue 26, 12016-12021, 09, 1986

Interfacial reaction dynamics and acyl-enzyme mechanism for lipoprotein lipase-catalyzed hydrolysis of lipid p-nitrophenyl esters

RA Burdette and DM Quinn

The fatty acyl (lipid) p-nitrophenyl esters p-nitrophenyl caprylate, p- nitrophenyl laurate and p-nitrophenyl palmitate that are incorporated at a few mol % into mixed micelles with Triton X-100 are substrates for bovine milk lipoprotein lipase. When the concentration of components of the mixed micelles is approximately equal to or greater than the critical micelle concentration, time courses for lipoprotein lipase- catalyzed hydrolysis of the esters are described by the integrated form of the Michaelis-Menten equation. Least square fitting to the integrated equation therefore allows calculation of the interfacial kinetic parameters Km and Vmax from single runs. The computational methodology used to determine the interfacial kinetic parameters is described in this paper and is used to determine the intrinsic substrate fatty acyl specificity of lipoprotein lipase catalysis, which is reflected in the magnitude of kcat/Km and kcat. The results for interfacial lipoprotein lipase catalysis, along with previously determined kinetic parameters for the water-soluble esters p- nitrophenyl acetate and p-nitrophenyl butyrate, indicate that lipoprotein lipase has highest specificity for the substrates that have fatty acyl chains of intermediate length (i.e. p-nitrophenyl butyrate and p-nitrophenyl caprylate). The fatty acid products do not cause product inhibition during lipoprotein lipase-catalyzed hydrolysis of lipid p-nitrophenyl esters that are contained in Triton X-100 micelles. The effects of the nucleophiles hydroxylamine, hydrazine, and ethylenediamine on Km and Vmax for lipoprotein lipase catalyzed hydrolysis of p-nitrophenyl laurate are consistent with trapping of a lauryl-lipoprotein lipase intermediate. This mechanism is confirmed by analysis of the product lauryl hydroxamate when hydroxylamine is the nucleophile. Hence, lipoprotein lipase-catalyzed hydrolysis of lipid p- nitrophenyl esters that are contained in Triton X-100 micelles occurs via an interfacial acyl-lipoprotein lipase mechanism that is rate- limited by hydrolysis of the acyl-enzyme intermediate.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				V. Seyrantepe, K. Landry, S. Trudel, J. A. Hassan, C. R. Morales, and A. V. Pshezhetsky Neu4, a Novel Human Lysosomal Lumen Sialidase, Confers Normal Phenotype to Sialidosis and Galactosialidosis Cells J. Biol. Chem., August 27, 2004; 279(35): 37021 - 37029. [Abstract] [Full Text] [PDF]

				J.-Q. Liu, T. Kurihara, M. Miyagi, S. Tsunasawa, M. Nishihara, N. Esaki, and K. Soda Paracatalytic Inactivation of L-2-Haloacid Dehalogenase from Pseudomonas sp. YL by Hydroxylamine. EVIDENCE FOR THE FORMATION OF AN ESTER INTERMEDIATE J. Biol. Chem., February 7, 1997; 272(6): 3363 - 3368. [Abstract] [Full Text] [PDF]