Colorimetric determination of the total protein eluted from latex gloves

TLDR: It was demonstrated that elution of the protein was very rapid, and changes of the extraction buffer volume had no appreciable effect on the extraction efficiency, and comparison experiments of the four assay methods revealed that Ninhydrin method was significantly interfered by low molecular weight substances other than protein and that Bradford method suffered from the poor reproducibility.

Abstract: Recently type I hypersensitivity reactions caused by latex gloves have been reported. The protein from latex gloves is considered to be responsible for this allergy. We investigated the extraction conditions and the assay methods for the purpose of the colorimetric determination of the total protein eluted from latex gloves. In a series of experiments, it was demonstrated that elution of the protein was very rapid, and changes of the extraction buffer volume (1.7-20 ml/g) had no appreciable effect on the extraction efficiency. Moreover, comparison experiments of the four assay methods revealed that Ninhydrin method was significantly interfered by low molecular weight substances other than protein and that Bradford method suffered from the poor reproducibility. On the other hand, Lowry method and Bicinchoninic acid (BCA) method gave relatively good results. Based on these experimental results, we established a typical procedure for quantitative analysis of the total protein as follows. Two grams of latex gloves specimens are extracted with 10 ml portions of phosphate buffered saline pH 7.4 (PBS) at room temperature for two hours, and then the resulting solution is assayed by BCA method. According to this procedure, commercially available ten kinds of latex gloves were analyzed. We found that the amount of the extractable protein was considerably varied with the products.