~ Protein ~ Structure

Review: Protein Structures Use the material provided to illustrate the 1°, 2°, 3° and 4° structures of protein. Keep in mind of the following terms:    - alpha helix     - beta pleated sheet     - hydrogen bond     - disulfide bond     - carboxyl and amino group 5 minutes

identify each structure explain their reasoning Go to another group and look at their model of protein structures to see if you can… identify each structure explain their reasoning 5 minutes

~ Protein ~ Digestion & Absorption

Review On the piece of paper provided draw a flow chart showing the process of protein digestion.     - Name the reactants and products     - Name the enzymes involved     - Name the hormones involved 5 minutes

Proenzymes or enzyme precursor or zymogen Chemicals Hormones Pepsinogen Pepsin Trypsinogen Trypsin Proenzymes or enzyme precursor or zymogen Protease Proteolytic enzymes Mucus HCl IF Denaturation: HCl breaks the hydrogen and disulfide bonds, thus disrupts the 2°, 3°, 4° structures of protein making the peptide bonds available to the enzymes. Gastrin CCK Secretin Stomach Intestine http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0007992.html

http://www.netterimages.com/image/8998.htm

http://www.netterimages.com/image/8998.htm

Protein Absorption AA are absorbed in the lumen of the small intestine Cross the membrane of enterocytes via active and passive transport Then cross the basolateral membrane into the capillaries AA circulate the blood stream to the liver

Food Allergies When larger peptides are absorbed The immune system responds to them Why is it that the majority of food allergies are caused by proteins? Food Allergies are different from food intolerance which produces an nonimmunological reaction The breakdown of proteins into amino acids is usually quite complete and typically results in the absorption of amino acids (not proteins) into the circulation. Sometimes, however, larger peptide chains are absorbed. When this happens, the body’s immune system may respond as if these peptides were dangerous. In such cases, the person is said to have an “allergic response,” or what is more commonly called a food allergy. Note, however, that not all adverse reactions to foods are true food allergies. A nonimmuneological reaction to a substance in a food is called a food intolerance (or food sensitivity). An example of a food intolerance is lactose intolerance.

Reading the Textbook Already read Structure: pg177-180 & pg183-187 Synthesis: based on class lecture Genetics: 188-189 Today Digestion & Absorption: pg189-193 Function: pg193-198

Homework Question AAs with similar R-groups are transported by the same transport protein into the blood Some experts recommend to avoid taking large quantities of certain amino acid supplements. Why? If amino acids A & B have chemically similar R-groups, then taking amino acid A supplements would negatively affect the transportation rate of amino acid B because A and B are transported by the same carrier proteins. Meaning that you may be absorbing a lot of amino acid A (from the supplement), but not enough amino acid B.