Title: Esterification of vertebrate-type steroids in the Eastern oyster (Crassostrea virginica). 
Resource Type: document --> technical publication --> journal article 
Country: EU Projects 
Year: 2004 
Availability: Janer G, Mesia-Vela S, Porte C, Kauffman FC (2004): Esterification of vertebrate-type steroids in the Eastern oyster (Crassostrea virginica). Steroids 69, 129-136 
Author 1/Producer: Janer G 
Other Authors/Producers: Mesia-Vela S, Porte C, Kauffman FC 
Author / Producer Type: EC Project 
Article Weblink (=direct link): http://www.comprendo-project.org/_files/Steroids2004ATAT.pdf  
Format (e.g. PDF): PDF 
EUGRIS Keyword(s): Contaminated land-->Contaminants-->Contaminants overview
 
Short description: Characteristics of acyl-coenzyme A (acyl-CoA):steroid acyltransferase from the digestive gland of the oyster Crassostrea virginica were determined by using estradiol (E2) and dehydroepiandrosterone (DHEA) as substrates. The apparent Km and Vmax values for esterification of E2 with the six fatty acid acyl-CoAs tested (C20:4, C18:2, C18:1, C16:1, C18:0, and C16:0) were in the range of 9–17 M E2 and 35–74 pmol/min/mg protein, respectively. Kinetic parameters for esterification of DHEA (Km: 45–120M; Vmax: 30–182 pmol/min/mg protein) showed a lower affinity of the enzyme for this steroid. Formation of endogenous fatty acid esters of steroids by microsomes of digestive gland and gonads incubated in the presence of ATP and CoA was assessed, and at least seven E2 fatty acid esters and five DHEA fatty acid esters were observed. Some peaks eluted at the same retention times as palmitoleoyl-, linoleoyl-, oleoyl/palmitoyl-, and stearoyl-E2; and palmitoleoyl-, oleoyl/palmitoyl-, and stearoyl-DHEA. The same endogenous esters, although in different proportions, were produced by gonadal microsomes. The kinetic parameters for both E2 (Km: 10M; Vmax: 38 pmol/min/mg protein) and DHEA (Km: 61 M; Vmax: 60 pmol/min/mg protein) were similar to those obtained in the digestive gland. Kinetic parameters obtained are similar to those observed in mammals; thus, fatty acid esterification of sex steroids appears to be a well-conserved conjugation pathway during evolution. 
Link to Project(s): COMPRENDO Comparative Research on Endocrine Disrupters - Phylogenetic Approach and Common Principles focussing on Androgenic/Antiandrogenic Compounds
 
Submitted By: Dr Stefan Gödeke WhoDoesWhat?      Last update: 14/02/2006