By DC

H2OH2O How much of you is protein?

Amino Acids: “Dry” form Carboxylic acid Amino group Radical group

Ionization? What’s it do in water? H+H+ H+H+ “wet” form

Amino Acids: (cont) 20 various radical groups nonpolarsome nonpolar polar or chargedsome polar or charged

Condensation or Dehydration Synthesis

Peptide bond Dipeptide dipeptide Synthesis of a dipeptide:

Protein Structure: The final shape of a protein determines its function Proteins are either globular or fibrous

Levels of Protein Structure: There are four possible levels of folding 1) Primary (1 0 ) 2) Secondary (2 0 ) 3) Tertiary (3 0 ) 4) Quaternary (4 0 )

Folding Nothing more than the amino acid sequence What forces hold it in this structure? ex? Lysozyme

Pro-Insulin- a globular protein Primary structure

Insulin- the finished hormone

Folding Actual folding Radicals not involved (yet) Forces responsible? Hydrogen Bonds Two possibilities  Helix &  Pleats

 Helix (first type found)

 Pleats (the second found)

Folding Results in final shape Actual folding Result of radical group interactions Four types of forces

Folding Bonding of two different polypeptides Covalently bonded

Denaturation of Proteins Destruction of its“native” configuration Environmental cause? 3-D shape is fragile temperature & pH changes

Support Keratin

Support Collagen

Enzymes Catalase Active site 2H 2 O 2 O2O2 2H 2 O

Transport Hemoglobin

Transport Channel Proteins

Transport Microtubules

Communication Hormones

Communication Receptor Proteins

Defense Antibodies

Motion Muscle fibers Actin Myosin