BIOMLS LAB proteins (precipitation reactions) expt8

proteins

exhibit amphoteric properties

acts like acids or bases

in the solution that depends on the pH proteins ________

heavy metals

high molecular wieght cations

negatively charged

proteins are what in pH of 7 and above

attracted

positive charged heavy metal is what to negative protein

protein precipitation

a laboratory technique that removes proteins from a solution by making them insoluble, causing them to aggregate and become solid particles that can then be separated

alkaloids

class of basic, naturally occuring organic compounds containing atleast one nitrogen atom

alkaloid reagent is negatively charged

when the pH of the solution is lower than the protein's isoelectric point the alkaloid reagents is what

protein is positively charged

when the pH of the solution is lower than the protein's isoelectric point the protein is what

denaturation

any changes in the 3d structure of the protein that makes it incapable of performing its normal function

Heat above 50 degrees Celsius

cause atoms in protein molecules to vibrate rapidly and disrupts weak hydrogen bonds and dispersion forces

use of organic compounds

will form new hydrogen bonds with proteins, disrupting intramolecular hydrogen bonding within the protein

salts of heavy metal ions

form a bond with the carboxylate groups within the amino acids which breaks its ionic bonds

alkaloid reagents

combine with positively charged amino groups in proteins to disrupt ionic bonds

inorganic acids

a compound of hydrogen and one or more element that dissociates or breaks down to produce hydrogen ions when dissolved in water or other solvents

positive charged protein molecule

upon addition of strong acids to neutral solutions of protein; carboxylate groups disassociate, nitrogen atmos become protonated, resulting in a positive charged protein molecule

protein will precipitate

what happens when ionic bonds and hydrogen bonds are disrupted

Heller's test

nitric acid test for protein denaturation; when nitric acid is added to a protein solution it causes protein denaturation and coagulation

white precipitation

effect of heller's test between two layers

Alcohol test

also causes protein denaturation; alcohol molecules form intermolecular hydrogen bonds with the polar groups of amino acids on its protein surface

alcohol

these compounds are capable of engaging in intermolecular hydrogen bonding with protein molecules

70% alcohol solution

is used as disenfectant on the skin; this concentration of alcohol is able to penetrate the bacterial cell wall and denature the proteins and enzymes inside of the cell

95% alcohol

coagulates the protein on the outside of the cell wall and prevents any alcohol from entering the cell

heat

can be used to disrupt hydrogen bonds and non-polar hydrophobic interactions; also one of the most common physical agents that can denature proteins

mechanism of heat

when temperature increases the kinetic energy of protein molecules also increases, causing the atoms and bonds within the protein to vibrate rapidly and violently that the bonds are disrupted

egg white is rich in protein

Why is egg white used as an antidote for heavy metals

poisoning?

yes, albumine denatures and precipitates when heated

Can heat coagulation test be used to detect the presence of albumin in urine?

they precipitate proteins on the surface of the burned area.

why is tannic acid and picric acid used in the treatment for burns