Proteins part 4

What is the product color of Biuret method?

• Copper binds to the peptide bond

• Protein + CuSO4 + NaOH + Rochelle salt = ____________

Biuret method is based on the formation of the violet-colored chelate between cupric ions and requires at least ______ peptide bonds. Measured at __________

In this method, molecules are formed when Urea is heated at 180◦C.

• 2 molecules of urea form _____ molecule of biuret

__________ is preferred for Biuret reaction

These will not be detected using a Biuret method.

What are the reagents used in Biuret method?

c. Rochelle’s salt = ___________________

• Used to complex Cupric ion and prevent their precipitation

• Keeps Copper in the Cupric form

• These 3 causes false increase in the range of Biuret method

• Causes false decrease levels

• Tyrosine & Tryptophan reduce PT-PMA reagent (folin-ciocalteu) to give a ______________

These reduces PT-PMA reagent

• F-CTM or Lowry Method detects proteins in low concentration, how low?

• Detects proteins in low concentration (10-60 ug/mL)

• Widely used in research to measure tissue and enzyme proteins

• Not satisfactory for urine and CSF protein determination

In Folin-ciocal Teu method, the specimens are mixed with an _______________ followed by the addition of the_____________

composed of phosphotungstic acid + molybdic acid which are used to reduce tungsten blue by copper complex with peptide and by tyrosine and tryptophan

Phosphotungstomolybdic acid is composed of?

What do phosphotungstic acid + molybdic acid reduce?