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Protein Chemistry

Ass.Prof./Naglaa Fathy Alhusseini

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Proteins chemistry

Definition:Proteins are organic nitrogenous compound of high molecular

weight, consisting largely or entirely of α-amino acids united together by peptide linkages.

They are composed of carbon, hydrogen, oxygen and nitrogen, many types of proteins may contain sulfur.

Nitrogen is a characteristic component of proteins, forming about 16% of their weight.

Functions of proteins:

Synthesis of tissue proteins e.g., contractile protein of muscles, collagen …etc...

Synthesis of cell organelles as cell membrane ,receptors…….etc

Synthesis of enzymes Synthesis of milk proteins. Synthesis of plasma proteins. Synthesis of protein hormones. Synthesis of nucleoproteins.

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Biological importance of proteins:

Fibrous or structural protein Keratin- elastin Collagen- reticulin Muscle protein (Myocin and Actin) Protein of cell membrane Protein of cytoplasm

Functional protein Enzyme Hormones Receptors Igs Plasma protein Hemoglobin

Questions

1- What are the biological importance of proteins?

All the following are functional protein EXCEPT

A. IgsB. enzymeC. CollagenD. Hemoglobin

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Amino Acids

Amino acid is an organic acid containing one or more amino group and carboxylic group (COOH)

carboxylic group (COOH) and amino group (NH2) are both attached to the α-carbon

They are the building units of protein.

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Representation of Amino Acid

NH2

H

R C

carboxylic group

amino group

side chain radicle

- carbon atom

COOH

Hydrogen atom