Novel Detection Methods For Metallothioneins As A Biomarker Of Heavy Metal Contamination And Their Applications

Metallothioneins (MTs), a class of specific proteins greatly induced by metals, are ubiquitous low molecular weight proteins characterized by high cysteine content. MTs are regarded as a biomarker of heavy metals exposure, knowned to have lots of biological functions such as storage of essential metals, detoxification of heavy metals, scavenging of free radicals and so on. Nowadays investigated as a popular topic. In the present there is no standard method to determine MTs and some existing methods have a lot of insufficients such as equipment demanding, operation complicating, difficulty in application. so sensitive, rapid and accurate analytical methods should been established in order to identify and quantify such substance.In the paper three methods were developed to detect the content of MTs by the technology of resonance light scattering(RLS).1.A novel detection method has been developed for MTs based on the technology of RLS using Alizarin red. In Britton-Robinson buffer solution of pH2.5 and the presence of sodium dodecylbenzene sulfonate, the intensity of system,s RLS was obviously enhanced because of interaction of MTs with alizarin red.The enhancement of RLS of the MTs-AR-SDBS system at 505nm was proportional to the concentration of MTs in the range of 0.0600~16.5μg/ml(r=0.9994).The detection limit was 19.05ng/ml and average recovery was 88.9%. The proposed assay succeeded in urinary sample determination with the advantages of simplicity and high sensitivity and good selectivity.2.Based on the formation of a multicomponent complex among mercury, portassium iodide , xylenol orange and metallothionein well distributed in pH2.5 buffer solution, a new detection method is established for MTs under the existence of Arabirgum-polyvinyl alcohol-124 as a steady agent.The enhancement of RLS at 505nm was proportional to the concentration of MTs ranging from 0.072~6.3μg/ml(r=0.9949).The detection limit was 21.58ng/ml with RSD 3.67%~5.61%, the average recovery was 91.0%(n=6). The method has been applied to the determination of metallothionein in spiked sample with satisfactory results.3.A novel quantitative method was developed for the determination of MTs using Light green SF (yellow) by technology of RLS.The enhancement of the system at 468nm was proportional to the concentration of MTs in the range of 0.052~5.0μg/ml, in the Britton-Robinson buffer solution(pH2.5) with the detection limit of 15.50ng/ml. The RSD was 1.01%～5.15%(n=9), and the average recovery was 92.7%.The method was sensitive and simple applied in the detection of MTs with satisfaction.This paper determined the content of urinary MTs and cadmium in different crowd by RLS method using alizarin red and graphite furnace atomic absorption spetrophotometry(GFAAS) respectively.The results showed that significant difference existed in the different crowd (P<0.001), moreover a correlation relationship existed between cadmium and MTs(r=0.585,P<0.001). Therefore the urinary MTs is important significance to assess environmental risk in heavy metal contamination area.