Abstract - Isolation and Characterization of the Early Nodule Specific Protein Homologue (Hev B 13), an Allergenic Lipolytic Esterase from Hevea brasiliensis Latex


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	Publications of MRB Latest Publications MRB Digest Journal of Rubber Research 3^rd Qtr 2008 Vol 11(3) 2^nd Qtr 2008 Vol 11(2) 1^st Qtr 2008 Vol 11(1) 4^th Qtr 2007 Vol 10(4) 3^rd Qtr 2007 Vol 10(3) 2^nd Qtr 2007 Vol 10(2) 1^st Qtr 2007 Vol 10(1) 1^st Qtr 2006 Vol 9(1) 2^nd Qtr 2006 Vol 9(2) 3^rd Qtr 2006 Vol 9(3) 4^th Qtr 2006 Vol 9(4) Submit paper/article Order Form	Abstract Isolation and Characterization of the Early Nodule Specific Protein Homologue (Hev B 13), an Allergenic Lipolytic Esterase from Hevea brasiliensis Latex S.A.M. Arif, R.G. Hamilton, F.Yusof, N.-P. Chew, Y.-H. Loke, S. Nimkar, J.J. Beintema and H.-Y. Yeang Recurring reports of a highly allergenic 42 - 46 kDa protein in Hevea brasiliensis latex appeared to have been resolved with the discovery of a 43 kDa allergenic latex protein that was a homologue to patatin. However, the low to moderate prevalence of sensitization to the protein - designated Hev b 7 - among latex-allergic patients could not adequately explain the frequent observations of the 42 - 46 kDa allergen. This led to the hypothesis that another, more allergenic, protein of a similar molecular weight existed in Hevea latex. We report the isolation and purification of a 42.98 kDa latex glycoprotein showing homology to the Early Nodule Specific Protein (ENSP) of the legumes Medicago sativa, Medicago truncatula and Glycine max. The protein is allergenic, being recognized by immunoglobulin E (IgE) in sera from latex-allergic patients. The IgE epitope resides on the protein's carbohydrate moiety, and the presence of a similar carbohydrate component on potato tuber patatin enables the latter to inhibit IgE-binding to the ENSP homologue. The cDNA encoding the ENSP homologue was isolated by RT-PCR and cloned. The protein predicted from the cDNA sequence has 391 amino acids, the first 26 of which constitutes a putative signal peptide. The deduced molecular weight of the mature protein is 40.40kDa while its isoelectric point is estimated at 5.0. The discrepancy between the predicted and observed molecular weights might be due to glycosylation, for which three N-sites on the protein are predicted. The purified protein showed lipase and esterase activities and may be involved in plant defense. back
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