Measurement of protein in natural rubber latex

Latex from the Brazilian rubber tree (Hevea brasiliensis) is the source of virtually all commercial natural rubber (cis-1,4-polyisoprene). Products made from natural rubber latex include gloves, condoms, and hundreds of different medical devices. However, recent reports of widespread life-threatening latex-associated Type I allergies have focused attention on latex proteins as serious allergens. In this paper, we describe a method that permits accurate and reproducible determination of protein in latex and that includes a procedure for solubilizing latex proteins and removing rubber. Also, we show that interfering substances in latex can be removed by precipitating proteins with sodium deoxycholate and trichloroacetic acid, and that latex proteins can be recovered and quantified with 2,2'-bicinchoninic acid.