Rapid and highly sensitive determination of trace proteins using dibromomethyl carboxyazo-Pb(II) complex as a spectroscopic reagent.
BACKGROUND
The concentration of protein in body fluids is an important measure in disease diagnosis and in analytical biochemistry. Searching for a sensitive and rapid method for proteins is an ongoing subject of investigation. We describe the reaction of dibromomethyl carboxyazo-Pb(II) with proteins found in urine.


METHODS
In a buffer containing of HCl and KCl at pH 1.80, dibromomethyl carboxyazo-Pb(II) complex combined with proteins to form a colored compound. The reaction was completed in 2 min and remained stable for 80 min. Under optimum conditions, the product of reaction between protein and dibromomethyl carboxyazo-Pb(II) absorbed at 530 nm and was linear in the range of 0-50 microg/ml of BSA. Moreover, the maximum binding number was defined to express the binding ability of dibromomethyl carboxyazo-Pb(II) to protein under a given set of conditions.


RESULTS
The method was applied to the determination of urine proteins. The recovery of protein from human urine was 97.6-103% and the precision was <4.8%. Results compared favorably to the Biuret and Bradford protein methods on 50 urine samples.


CONCLUSIONS
This method had high sensitivity and specificity and may be applicable to clinical analysis.
Wei
Qin
Q
School of Chemistry and Chemical Engineering, Jinan University, China. sdjndxdb@163.com
Li
Yuan-Yuan
YY
Li
Yan
Y
Du
Bin
B
Duan
Cai-Hong
CH
D000818:Animals; D002021:Buffers; D002417:Cattle; D002645:Chickens; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis* / Q000737:chemistry*; D009942:Organometallic Compounds / Q000032:analysis* / Q000737:chemistry*; D009994:Osmolar Concentration; D010047:Ovalbumin / Q000737:chemistry / Q000652:urine; D011489:Protein Denaturation; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis / Q000737:chemistry; D012996:Solutions; D013053:Spectrophotometry / Q000379:methods*; D013379:Substrate Specificity; D013997:Time Factors; D014556:Urine / Q000737:chemistry; D005719:gamma-Globulins / Q000737:chemistry / Q000652:urine
D002021:Buffers; D009942:Organometallic Compounds; D012709:Serum Albumin; D012996:Solutions; C507163:dibromomethyl carboxyazo-Pb(II); D005719:gamma-Globulins; D007854:Lead; D010047:Ovalbumin