Proteins- Definition, Properties, Structure, Classification, Functions

Proteins- Properties, Structure, Classification and Functions

What are Proteins? Proteins are the most abundant biological macromolecules, occurring in all cells. It is also the most versatile organic molecule of the living systems and occurs in great variety; thousands of different kinds, ranging in size from relatively small peptides to large polymers. Proteins are the polymers of amino acids covalently linked by the peptide bonds. The building blocks of proteins are the twenty naturally occurring amino acids. Thus, proteins are the polymers of amino acids. Properties of … Read more

Biuret Test for Protein- Definition, Principle, Procedure, Results, Uses

Biuret Test for Protein

What is Biuret Test? Proteins are complex compounds formed by thousands of amino acids. Amino acids are amphoteric electrolytes having carboxyl and amino groups that act like acid and base. It has one positive charge and one negative charge, hence these ions are electrically neutral and do not migrate in the electric field. The two amino acids are linked together with the help of a bond called peptide bond and it yields dipeptide. The bond is formed between the α … Read more

Membrane Proteins

Membrane Proteins

Biological membranes consist of a continuous double layer of lipid molecules in which membrane proteins are embedded. Although the lipid bilayer provides the basic structure of biological membranes, the membrane proteins perform most of the membrane’s specific tasks and therefore give each type of cell membrane its characteristic functional properties. The amounts and types of proteins in a membrane are highly variable. In the myelin membrane, which serves mainly as electrical insulation for nerve-cell axons, less than 25% of the … Read more

Solubility Tests of Proteins- Definition, Principle, Procedure, Result, Uses

Solubility Tests of Proteins

Solubility Tests of Proteins Definition Solubility tests are tests performed to determine the ability of compounds to dissolve in a solvent, which is usually a liquid. These tests are essential to determine the size and polarity of unknown compounds and the presence of acidic and basic functional groups. Solubility tests for proteins and amino acids are qualitative tests that determine the presence and absence of different proteins. The determination of the solubility of proteins is an important factor that provides … Read more

Hopkin’s Cole Test- Definition, Principle, Procedure, Result, Uses

Hopkin’s Cole Test

Hopkin’s Cole Test Definition Hopkin’s Cole test is a specific test used for the detection of indole ring and thus, tryptophan in proteins. The test is also termed as ‘glyoxylic acid test’ as the reagent contains glyoxylic acid. The test was discovered by Frederick Gowland Hopkins and Sydney W. Cole in 1901 as a part of their work on the discovery of tryptophan. Hopkin’s Cole test is extremely similar to the Adamkiewez reaction, which is similar in principle to this … Read more

Heller’s Test- Definition, Principle, Procedure, Result, Uses

Heller’s Test

Heller’s Test Definition Heller’s test is a biochemical test performed to detect proteins in a sample by the denaturation of those proteins by the addition of strong acids. Heller’s test usually uses concentrated nitric acid for the denaturation of proteins. The test is performed for clinical purposes to detect abnormal proteins in biological fluids, including urine. Heller’s test is a type of precipitation test where the precipitation is brought about by denaturation. The test was discovered and named after the … Read more

Heat coagulation test of proteins

Heat coagulation test of proteins definition Heat coagulation test of protein is a biochemical test performed to determine the presence of proteins like albumin and globulin in protein. Coagulation of proteins as a response to heat is a common phenomenon. The heat coagulation of proteins occurs in one of the two stages; denaturation and agglutination or the separation of the denatured protein in a particular form. The heating of coagulable proteins at their isoelectric pH, a series of changes occur … Read more

Esbach Test- Definition, Principle, Procedure, Result, Uses

Esbach test

Esbach test definition Esbach test is one of the oldest biochemical tests used to detect urinary protein like albumin when the urine is combined with citric and picric acid. Esbach test, even though not discussed much through the history, is useful for both qualitative and quantitative determination of albumin in the urine sample. The test was discovered by Georges Hubert Esbach in 1874 as one of the earliest attempts at quantification of albumin in the urine. Esbach test has continuously … Read more

Digestion and Absorption of Carbohydrates, Proteins and Fats

Digestion and Absorption of Carbohydrates, Proteins and Fats

Digestion and Absorption of Carbohydrates, Proteins, and Fats Carbohydrates, fats, and proteins are the major nutrients the body needs for growth, repair, movement, and maintaining tissue and organ function. These macromolecules are broken down and absorbed into the body at different rates and into specific forms as they travel through the organs in the digestive system. Digestion of carbohydrates Among carbohydrates, only the monosaccharide forms are absorbed. Hence, all carbohydrates must be digested to glucose, galactose, and fructose for absorption … Read more

Homology Modeling- Working, Steps, and Uses

Homology Modeling- Working, Steps, and Uses

Homology modeling is also known as comparative modeling predicts protein structures based on sequence homology with known structures. It is based on the principle that “if two proteins share a high enough sequence similarity, they are likely to have very similar three-dimensional structures.” It hence relies on the identification of one or more known protein structures likely to resemble the structure of the query sequence, and on the production of an alignment that maps residues in the query sequence to residues in … Read more