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Proteins
Proteins
• Other than water, protein are the chief
constituents of the cells of the body.
• Proteins are much more complex than
carbohydrates or lipids.
• All proteins contain the elements carbon,
hydrogen oxygen and nitrogen.
• Some also contain sulfur, phosphorus.
Proteins
• Proteins function in the body in building of
new cells.
• Also in the maintenance of existing cells.
• Also in the replacement of old cells.
• Proteins are the most important
compounds in the body.
• They are also valuable source of energy in
the body.
Proteins
• They are involved in the regulation of metabolic
processes.. Hormones.
• Also in the catalysis of chemical reaction..
Enzymes.
• In the body’s defense against infection.
• In the transmission of impulses
• In the transmission of hereditary characteristics.
• Are components of the skin, hair, nails, and
connective tissues.
Amino acids
• Proteins are polymers built up of simple
units called amino acids.
• Hydrolysis of proteins yield amino acids .
• Is an organic acid that has an amine group
attached to a chain containing an acid
group
• The amine group ( --NH2) can be
anywhere on the chain.
Amino acids.
• The body can synthesize some, but not all of the
amino acids it needs
• Those it cannot synthesize must be supplied in
food.--- Essential amino acids.
• These are Isoleucine, Leucine, Lysine,
Methionine, Phenylalanine, Threonine,
Tryptophan, Valine, Histidine
• The non essential amino acids are…Alanine,
arginine, Asparagine, Aspartic acid, cystein,
cystine, glutamic acid, glutamine, glycine,
ornanthine, proline, serine, Taurine, Tyrosine.
Isoleucine
Leucine
Proteins
• Proteins consist of many amino acids held
together by Peptide linkage
• When 2 aminoacids combine,the product is
called a dipeptide. When 3..Tripeptide.
• When protein is hydrolyzed, it breaks down into
smaller units and eventually forming amino
acids.
• Likewise when amino acids combine, they form
dipeptides, tripeptides then eventually proteins.
Peptide bond
Classification
• 3 categories.
• Simple, conjugated, and derived.
• Simple proteins yield only amino acids on
hydrolysis e.g. albumin, globulins
• Conjugated proteins consist of a simple protein
combined with a non protein compound e.g.
lipoprotein, glycoprotein, phosphoproteins.
• On hydrolysis, conjugated proteins yield amino
acids and some other types of compounds.
Proteins
• Derived proteins are produced by action of
chemical, enzymes, on the other 2 types
of proteins.
• Derived proteins include proteoses,
peptones, polypepetides, tripeptides and
dipeptide.
• Proteins are also classified according to
solubility, composition, function and
shape.
Structure of albumin