0
Ninhydrine [2,2-Dihydroxyindane-1,3-dione] is equilibrating with [indane-1,2,3-trione] + H2O.
Two molecules of this triketon react each with their number 2 carbonyl in two steps:
- The first step is when a free amino group of the amino acid reacts with it the carbonyl group and gives free H2O, CO2 and a Shiff-base, that will be followed by hydrolysed ( + H2O) an aldehyde and an Amine [2-Amino-indane-1,3-dione]
- In the second step this Amino group gets (again) coupled to a second triketone molecule [indane-1,2,3-trione] and an Imine-di-(Indane-1,3-dione) is formed (with H2O given free).
With proline and hyroxy proline no blue color can be seen due to the fact that the first step will stop right after decarboxylation is completed, because the following hydrolysis of the Schiff-base is NOT possible. It turns yellowish brown instead.
What else can I help you with?
Why ninhydrin shows positive test for amino acid and protein?
Ninhydrin reacts with ammonia, a primary amine, or a secondary amine (amino acids have a primary or alpha amino group, except for proline which has a secondary amino group). They all turn purple/blue right away upon heating with ninhydrin.Remember that a protein has a amino terminal and a -COOH terminal. The ninhydrin will react with the amino terminal giving a very light blue or violet color (more often than not you will see no color change). Upon further heating you may notice an increase in the intensity of the blue/violet. this is due to the heat denaturing the protein, thereby exposing more -NH2 groups for the ninhydrin reagent to react with
Amino acids contain two common functional groups an amino group and an?
Amino acids contain two common functional groups - an amino group (-NH2) and a carboxyl group (-COOH). These groups give amino acids their distinctive properties and are involved in forming peptide bonds between amino acids to create proteins.
Will Alanine give a negative Biuret test?
Yes, alanine will give a negative Biuret test. The Biuret test is used to detect the presence of proteins, which are made up of long chains of amino acids. Since alanine is a single amino acid, it will not give a positive response in the Biuret test.
What are the names of the two chemical groups that all amino acids have in common?
Amino = Amine Acid = Carboxylic Acid These two groups are what give amino acid's there name. Source: http://en.wikipedia.org/wiki/Amino_acid
How many amino acids do living organisms contain?
Living organisms contain 20 standard amino acids that are used to build proteins. These amino acids have different side chains that give each one unique characteristics and functions in biological processes.
What color develops when ninhydrin react with amino acids?
These are the amino acids that will yield positive result to the ninhydrin test: Non-polar amino acids: Glycine, Alanine, Valine, Leucine, Isoleucine, Phenylalanine, Methionine, Tryptophan Polar Neutral Amino acids: Serine, Cysteine, Threonine, Asparagine, Glutamine, Tyrosine Polar Acidic Amino Acids: Aspartic acid and Glutamic acid Polar Basic Amino Acids: Histidine, Lysine, Arginine
What funtional group will give a positive results with ninhydrin reagents?
Amino groups (NH2) will give a positive result with ninhydrin reagent, forming a purple-colored complex when reacted. This reaction is commonly used to detect the presence of amino acids, peptides, and proteins.
Why proline amino acid gives yellow colour in reaction with ninhydrin?
Yes. Within "The Chemical Reactions of Amino Acids / Reactions of Amino Groups" there are several examples - one of which is the ninhydrin reaction. A very widely applied reaction of the alpha amino group [that is the N in the peptide bond -CCN-CCN-], it is used to estimate the quantity of amino acids [in a sample] in very small amounts. All amino acids and polypeptides with a free alpha group react with ninhydrin and yield [or produce] an intensely purple colored product - except for Proline and Hydroxyproline {both in which the alpha amino group is termed to be 'substituted' - something to do with carbon rings} which "yield derivatives with a characteristic yellow color." See also 'Schiff's bases'.
Why ninhydrin shows positive test for amino acid and protein?
Ninhydrin reacts with ammonia, a primary amine, or a secondary amine (amino acids have a primary or alpha amino group, except for proline which has a secondary amino group). They all turn purple/blue right away upon heating with ninhydrin.Remember that a protein has a amino terminal and a -COOH terminal. The ninhydrin will react with the amino terminal giving a very light blue or violet color (more often than not you will see no color change). Upon further heating you may notice an increase in the intensity of the blue/violet. this is due to the heat denaturing the protein, thereby exposing more -NH2 groups for the ninhydrin reagent to react with
Why amino acids give yellow colour with nitric acid?
When amino acids react with nitric acid, a yellow color may be observed due to the formation of nitro compounds. Nitric acid can nitrate amino acids, leading to the production of yellow-colored nitro derivatives. The specific yellow color observed can vary depending on the amino acid present and the reaction conditions.
Amino acids contain two common functional groups an amino group and an?
Amino acids contain two common functional groups - an amino group (-NH2) and a carboxyl group (-COOH). These groups give amino acids their distinctive properties and are involved in forming peptide bonds between amino acids to create proteins.
What group do amino acids always contain?
The amino acids are distinguished by the R groups which determines what amino acid it is.
Which pair of functional groups are involved in the reaction of amino acids to give peptides?
The functional groups involved in the reaction of amino acids to give peptides are the amine group (-NH2) and the carboxyl group (-COOH).
All amino acid having an aromatic ring give a positive xanthoproteic test under identical condition?
No, not all amino acids with an aromatic ring give a positive xanthoproteic test. The xanthoproteic test is mainly positive for amino acids containing aromatic rings with phenolic groups such as tyrosine and phenylalanine. Aromatic amino acids like tryptophan do not give a positive xanthoproteic test under identical conditions.
How many amino acids were changed?
To determine how many amino acids were changed, you would need to compare the amino acid sequences of the original and mutated proteins. By aligning the two sequences, you can count the positions where the amino acids differ. This count will give you the total number of changed amino acids. If you provide specific sequences or context, I can help you analyze them further.
Will Alanine give a negative Biuret test?
Yes, alanine will give a negative Biuret test. The Biuret test is used to detect the presence of proteins, which are made up of long chains of amino acids. Since alanine is a single amino acid, it will not give a positive response in the Biuret test.
What amino acids give positive Ehrlich test?
Amino acids that contain an indole group, such as tryptophan, give a positive Ehrlich test. The Ehrlich test is a colorimetric test that detects compounds containing indole or phenolic groups by producing a pink or red color when reacted with p-dimethylaminobenzaldehyde reagent.
