The intent of this experiment is to obtain information about structural of a compound with some trials these are biuret, ninhydrine, xanthoprotic and heavy metal group by detecting color alterations or non.

Casein is a protein that is found in milk and used as a binding agent. Technically, phosphoproteins, aggregations of proteins bound to something incorporating phosphorous acid. [ 1 ]

Albumin is an umbrella term for a type of protein which is H2O soluble. Albumin can be found two of the most familiar illustrations that are in egg Whites and in human blood. Albumins are an of import category of protein, and they are vitally of import to wellness and good being for many beings. Many workss and animate beings contain or secrete albumen. [ 2 ]

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Tyrosine is a incidental amino acid the organic structure makes from another amino acid called phenylalanine. It is a edifice block for several of import neurotransmitters, 5-hydroxytryptamine, Dopastat etc. Neurotransmitters help steel cells communicate and influence temper. Tyrosine besides helps bring forth melanin ( the pigment responsible for hair and clamber colour ) and helps in the map of variety meats responsible for doing and modulating endocrines. It is involved in the construction of about every protein in the organic structure. [ 3 ]

Protein Testing:

Biuret Trial: The Biuret Test is a general trial to observe peptide bond or non. When protein that includes peptide bond reacts with Cu ( II ) sulphate ( bluish ) , the positive trial is the formation of a violet colored complex.

The Biuret Test works for any compound incorporating two or more of the undermentioned groups.

Ninhydrin Trial: The Ninhydrin Test is a trial for amino acids and proteins to observe free -NH2 group. When such an -NH2 group reacts with ninhydrin, a purplish-blue composite is formed.

Xanthproteic Trial: Phenyl group incorporating an triping group can be nitrated it produces as a xanthous merchandise.

The production of a xanthous coloured merchandise provide by the add-on of azotic acid and this trial works for the presence of tyrosine or tryptophan in a protein.The add-on of strong base will intensify the colour to orange. The xanthous discolorations on the tegument caused by azotic acid are the consequence of the xanthoproteic reaction.

Heavy Metal Ions Test: Heavy metal ions precipitate proteins by cross-linking free amino groups and carboxylate groups.

Ions normally used for proving for the presence of proteins include Zn2+ , Fe3+ , Cu2+ , Sb3+ , Ag1+ , Cd2+ , and Pb2+ .

Among the metal ions, Hg2+ , Cd2+ , and Pb2+ have really high toxicity. They cause serious harm to proteins ( particularly enzymes ) by denaturing them. [ 4 ]

Apparatus

Dropper

Test tubing

Heater

% 2Casein

% 2Albumin

% 2Gelatin

% 2Glycine

% 2Trypthophan

NaOH

Copper sulphate

Ninhydrine reagent

Nitric acid

Milk

Silver nitrate

Iron nitrate

Sodium nitrate

Water Bath

Procedure

Biuret Test

First, % 2 solutions ; glycine, gelatin, albumen, thyrosine and casein were prepared.

These tubings were labelled as 1,2,3,4 and 5

1ml of each solution except casein and put caserin with 1 ml H2O.

7-10 beads NaOH and 2 beads Cu sulphate solution on each of the samples to be tested.

Observations were recorded.

Ninhydrine Trial

New trial tubings were labelled once more.

7-10 beads of ninhydrin reagent were added to each trial tubing and heated in H2O bath about 5 min.

Observations were recorded.

Xanthoproteic Trial

New trial tubings were labelled

10-15 beads of azotic acid were added to each trial tubing and heated in H2O bath about 10min.

Observations were recorded.

Heavy Metal Precipitation

1.2ml milk were put into glycine, gelatine and albumen labelled as 1,2,3

2.10 beads of % 5silver nitrate were added to glycine,10 beads of Fe ( III ) nitrate to gelatine and 10 beads of Na nitrate to prove tubing albumen.

3.These stairss were repeated for % 2 albumen.

4.Finally, observations were recorded.

Observation

In this experiment, we placed new trial tubing into rack by labeled each with number.The ground of that is to use some trials to each one.These trials are biuret, ninhydrine, xanthoproteic and heavy metal tests.Casein, albumen, gelatin, glycine and tyrosine were tested with biuret test.Firstly inside bluish bed with casein and so light purple at top of tubing and bluish layer.In albumen, the violet coloring material diffused in trial tubing, and so purple at top and violet bed at underside. With gelatin, at top is violet as a first and so violet atoms were besides observed.For glycine, blue appeared as homogenous like dissolved.And so at top is bluish, at underside like green.Final consequence for biuret trial is for tyrosine.At the beginning, bluish bed was remained in suspense and so green, brown atom was observed at underside.

Second, ninhydrine trial consequences were recorded for each one.With casein, we observed light purple like grey.With gelatin, glycine and besides tyrosine dark purple.With albumen, the colour appeared like dark purple due to heater.

Third, the other trial is xanthoprotic trial to observe easy phenyl group.With casein, opaque turned into xanthous particles.With gelatin and glycine, the coloring material is so light yellow like colourless.With tyrosine, xanthous colour turned into brown in time.Finally, albumin appeared as cloudy white and so turned into xanthous atoms.

Concluding trial is heavy metal trial that gives information about structure.Milk with Ag nitrate turned into pink due to density.With Fe and Na nitrate, there are no alterations.

Consequence

In this experiment, we learned some trial to obtain information that we searched.For illustration, Biuret trial is aid to give information about peptide bond or not.If there is a peptide bond, the colour is observed as purple.If the coloring material is bluish, it means no rxn there.Casein, albumen, gelatin, glycine and tyrosine were tested.Casein, albumen and gelatin gave violet colour and these 1s have peptide bond.Because these are proteins that have peptide bonds.However, glycine and tyrosine are non proteins one of them is aminoacid the other is enzyme.Therefore they did non give rxn non observed violet colour as we expected.

With ninhydrine trial, except casein, the others gave pozitive rxn appeared as purple color.This trial is to assist information about free amino group primary or secondary.The other trial is xantroprotic test.It gives information about phenyl group.Aromatic group one is yellow.Nitric acid is used to prove it.This reaction is besides endothermal rxn.Casein and tyrosine gave reaction and observed colour changes.The concluding trial is heavy metal test.It helps to give information about construction of a compound.If protein is tested with heavy metal, coloring material alterations are ascertained also.It is tested with Ag, Fe and Na nitrate also.Silver helps to distrupt the construction that means colour change.With Ag, the colour turns into pink.

Discussion

The intent of this experiment is to larn which trial why is used.Biuret trial is to observe there are peptide bond or not.Normally, biuret trial can give pozitive consequence that means violet colour with proteins.In our experiment, casein albumen and gelatin spring ( + ) consequence nevertheless glycine and tyrosine non due to aminoacid or enzyme.Our consequences are besides related to as we expected.Ninhydrine trial was applied to same prepared samples.The purpose of this trial is to observe free aminogroup ( -NH2 ) and to make up one’s mind primary or secondary group harmonizing to the colour.We used warmer in this part.The ground of that reaction go a world due to endothermic.At this portion, except casein the others could give ( + ) result.Glycine that we learned old experiment can hold free aminogroup ( primary ) .With casein, the others colour turned into dark purple.

The other trial is xandroprotic trial that is used to observe phenly group.It helps to know apart aromatic construction from others.For casein, the coloring material turned into xanthous, for tyrosine, the coloring material turned xanthous to orange like brown.Therefore, two of them could give pozitive result.As a concluding trial, heavy metal trial was applied to fix samples.This trial shows which sample can distrupt with which one.Silver, Fe and Na nitrate were used to observe it.Silver can distrupt protein structure.We understood that colour changes.The colour turns into pink and the others did non alter for milk ( nesquick ) .

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