The nitrogen content of various proteins is very close, with an average of about 16%. The protein content in 100g sample = grams of nitrogen per gram of sample * 6.25 * 100

There are only 20 types of amino acids that make up human protein

General structural formula

structure

Structure and classification

The α-carboxyl group of an amino acid molecule and the α-amino group of an amino acid molecule undergo dehydration and condensation to form a covalent bond.

Two amino acids are condensed into dipeptides, three are tripeptides, less than ten are oligopeptides, 10-50 are polypeptides, and more than 50 are proteins.

Glutathione (GSH)

The length of the peptide bond is between single and double bonds, so it has the properties of a partial double bond and cannot rotate freely, so that the six atoms involved in the formation of the peptide bond are on the same plane.

right hand spiral

The R group side chain is outside the helix

3.6 residues per turn, pitch 0.54nm

Maintained by hydrogen bonds, the central axis is parallel

Fully extended, serrated

Single reply/multiple parallels

The R-based side chains are staggered up and down the plane

cisparallel and antiparallel

Maintained by hydrogen bonds, perpendicular to the long axis

Hydrophobic bond Ionic bond (salt bond) Hydrogen bond Van der Waals force

Folded into a tight ball shape

Contains a variety of secondary structural units

Hydrophobic groups are located inside the molecule and hydrophilic groups are located on the surface of the molecule

Mainly maintained by secondary bonds

Composed of multiple peptide chains (subunits)

Subunits can be the same or different

Subunits are linked by non-covalent bonds

Polymerization and depolymerization between subunits

hydrogen bond ionic bond

positive synergy

allosteric effect

Under the action of certain physical and chemical factors, the specific spatial conformation of proteins is destroyed, resulting in changes in their physical and chemical properties and loss of biological activity.

Produce and store protein hormones, enzymes, antibodies and serum under low temperature conditions to prevent their denaturation and inactivation

Disinfect with alcohol and ultraviolet steam to denature the proteins of viruses and bacteria to achieve the purpose of sterilization

Purple red complex

purple compound