Two dye-binding reagents, 2-(4’.hyd roxybenzeneazo)benzoic acid (HABA) and bromcresol green (BCG), for the quantitation of serum albumin have been compared with the biuret colorimetric procedure after salt fractionation. The linear regression equations for the biuret-BCG and the biuretHABA comparisons were y = 0.43 + O.9lx and y = -0.45 + l.l5x, respectively. Their corresponding correlation coe...

In assay of serum proteins by use of the biuret reaction, dextran can cause turbidity by formation of an insoluble complex of dextran with copper and tartrate (or EDTA) in strongly alkaline solution. Whether or not the turbidity occurs depends on the tartrate concentration: turbidity is maximal at about 10 g/L, absent at 20 g/L or more, and only slight and delayed at 4 g/L. Two biuret reagents,...

QUANTITATIVE determinations of serum and urinary proteins are of considerable clinical importance; that such estimations are made relatively infrequently is probably due to the lack of a simple yet trustworthy technique. The methods of Esbach and Aufrecht are notoriously crude, while the gravimetric and the Kjeldahl methods are too laborious for ordinary clinical purposes. Of the colorimetric p...

We describe a procedure for measuring total protein in urine. The method is simple, sensitive, and free of interference from drugs that are known to affect other commonly used methods. The CV for a 1.1 g/liter urine control in daily, routine use is 4.6%. The procedure involves adsorbing the protein onto cellulose powder, binding of Ponceau S dye by the protein, washing away excess dye, and elut...

Five ruminally and duodenally cannulated steers (491 +/- 21 kg BW) were used in an incomplete 5 x 4 Latin square with four 24-d periods to determine the influence of supplemental nonprotein N (NPN) source and supplementation frequency (SF) on the dynamics of ruminal fermentation in steers consuming low-quality grass straw (4% CP). Treatments (TRT) included an unsupplemented control (CON) and a ...

Rapid synthesis of symmetrical 1, 3disubstituted urea derivatives from biuret and different substituted anilines has been carried out in presence of Sodium chloride (NaCl) in dry media. Diverse substituted anilines were reacted with biuret in 2:1 molar ratio to give the corresponding urea derivatives. The reaction conditions were clement, solvent free, mild and the products were attained in goo...

This communication describes and evaluates an improved routine methodology for quantitating clinical proteinuria. Based on investigations of Piscator and of Savory et al., a modified Tsuchiya's reagent (ethanolic HCI-phosphotungstic acid) is used to precipitate proteins at 56 degrees C, followed by biuret spectrophotometry at 540 nm. The accuracy of the proposed procedure was assessed by compa...

IT HAS BEEN POINTED OUT PREVIOUSLY that the method for the assay of urinary peptides using the biuret reagent is a much simpler procedure than others in current use (1). However, a disturbing difficulty with this method has been the lack of reproducibility of the biuret reagent (1). This resulted in sporadic errors approximately 10 per cent and in a feeling of uncertainty regarding the method i...

Five steers (491 +/- 21 kg BW) were used in an incomplete 5 x 4 Latin square with four 24-d periods to determine the influence of supplemental non-protein N (NPN) source and supplementation frequency (SF) on nutrient intake and site of digestion in steers consuming low-quality grass straw (4% CP). Treatments (TRT) included an unsupplemented control and a urea- or biuret-containing supplement pl...