burlington tests business administration financeDescripción completa
STRUKTUR PROTEINFull description
Membahas tentang definisi, mekanisme terjadinya, sebab, dan contoh terjadinyaDeskripsi lengkap
Deskripsi lengkap
Full description
Mengenai protein
kolagen
proteinDeskripsi lengkap
kelarutan protein
tugas BiokimiaDeskripsi lengkap
PPT Protein mata kuliah teknologi pembelajaran kimia UNNES menerapkan aplikasi chemdraw, hyperchem, dan chemdraft.Deskripsi lengkap
MKGKGKDeskripsi lengkap
Deskripsi lengkap
Deskripsi lengkap
doneFull description
Mengenai protein
Janir Ty Datukan Datukan Department of Physical Sciences College of Science Philippine Normal University
Outline
Colorimetric Test Biuret Test Ninhydrin Ninhydrin Test Test Xanthoproteic Xanthoproteic Test Millon-Nasse Test Hopkins-Cole Reaction Sakaguchi Reaction Lead Lead Acetate Acetate Test Test
Outline
Colorimetric Test Biuret Test Ninhydrin Ninhydrin Test Test Xanthoproteic Xanthoproteic Test Millon-Nasse Test Hopkins-Cole Reaction Sakaguchi Reaction Lead Lead Acetate Acetate Test Test
Outline
Precipitation Reaction of Proteins Heat and Acid Alcohol Alkaloidal Reagents Reagents Heavy Metal Salts Isoelectric Point Salting Out
Chromatography Chromatography Analysis Analysis
Biuret Test
Quantitative photometrical determination of total protein concentration Protein must have at least three peptide bonds Positive test produces a blue- to violet-colored solution Intensity of color depends on the number of peptide bonds present in the sample Biuret Reagent is made from potassium hydroxide and hydrated copper(II) sulfate
Biuret Test
Ninhydrin Test
2,2-Dihydroxyindane-1,3-dione is a chemical used to detect ammonia or primary & secondary amines Positive test results in deep blue or purple color known as Ruhemann's purple Commonly used to detect fingerprints due to the terminal amines or lysine residues in peptides and proteins
Xanthoproteic Test The aromatic groups in the amino acids can undergo nitration with nitric acid and give in yellow-colored products Only phenyl rings containing an activating group can be nitrated Phenylalanine doesn’t undergo nitration because it’s not activated like tryptophan and tyrosine
Millon-Nasse Test Millon-Nasse reagent is made from by dissolving metallic mercury in nitric acid and diluting with water May also be prepared from mercury metal dissolved in H2SO4 Detects phenolic groups, which means only for tyrosine Positive result produces a red-brown solution or precipitate
Millon-Nasse Test
http://www.drugs.com/dict/millon-nasse-test.html
Hopkins-Cole Reaction
Specific test for the indole ring in the amino acid tryptophan Hopkins-Cole reagent contains glyoxylic acid (Mg powder, oxalic acid, acetic acid) and concentrated H2SO4 Positive reaction will show a purple-colored ring in the solution boundaries
Sakaguchi Reaction A colorimetric reaction for identification and quantification of guanidinium group of arginine Reagent includes α–naphthol and sodium hypobromite (NaBrO) or bromine water in alkaline solution Positive test results in an orange- to red-colored solution
Tests for the presence of sulfur from cysteine and methionine Reagent includes sodium hydroxide and lead(II) acetate Boiling with NaOH converts S in the amino acid to NaS, which then precipitates as balck PbS with the addition of lead acetate Positive result is a black solution or precipitate
Heat and Acid Heat disrupts hydrogen bonds of secondary and tertiary protein structure The primary structure remains unaffected The protein increases in size due to denaturation and coagulation occurs Addition of acetic acid to albumin results in the formation of a cloudy white substance called a coagulum
Alcohol Hydrogen bonding occurs between amide groups in the secondary protein structure Hydrogen bonding between "side chains" occurs in tertiary protein structure in a variety of amino acid combinations All of these are disrupted by the addition of another alcohol
Alkaloidal Reagents Alkaloidal reagents (e.g. tannate & trichloroacetate) are high molecular weight anions The negative charge of these anions counteracts the positive charge of the amino group in proteins This results in the formation of a precipitate
Heavy Metal Salts
Heavy metals (e.g. Hg2+, Pb2+, Cu2+) are high molecular weight cations The positive charge of these cations counteracts the negative charge of the carboxylate group in proteins This results in the formation of a precipitate Heavy metals may also disrupt disulfide bonds because of their high affinity and attraction for sulfur This will also lead to the denaturation of proteins
The solubility of protein depends on the pH of the solution It is positively charged at low pH and negatively charged at high pH The pH at which a protein molecule has a net charge of zero is called the isoelectric point In general, the net charge, either positive or negative, can interact with water molecules Therefore, a protein is the least soluble when the pH of the solution is at its isoelectric point
Salting Out
Protein molecules contain both hydrophilic and hydrophobic amino acids In aqueous medium, hydrophobic amino acids form protected areas whil hydrophilic amino acids form hydrogen bonds with surrounding water molecules (solvation layer)
Salting Out In salt solutions (e.g. ammonium sulfate), some of the water molecules in the solvation layer are attracted by salt ions When salt concentration gradually increases, the number of water molecules in the solvation layer gradually decreases The protein molecules then coagulate forming a precipitate; this is known as salting out
