Genes, Polypeptides and Enzymes One Gene – One Polypeptide Hypothesis

Exceptions to this rule: some genes = tRNA or mRNA not polypeptides

DNA sequences as gene regulators..not translated into proteins

Introducing Enzymes They are catalysts so the make reactions easier

This increases productivity and yield Globular proteins As catalysts they are not consumed by the reaction

The may be used over and over again Enzymes show specificity to the reaction they

control Enzymes are sensitive to their environment so they

can be controlled by adjusting the temperature, the pH or the substrate concentration

© 2008 Paul Billiet ODWS

Enzymes have been used in biotechnology for millennia

http://www.touregypt.net/featurestories/bread.htm

© 2008 Paul Billiet ODWS

Lactase Lactase is used to remove the sugar lactose

from milk and other dairy products

© 2008 Paul Billiet ODWS

Lactose intolerance Some people are intolerant of lactose in milk they

cannot digest it The lactose remains in the digestive system and is

fermented by bacteria The result is nausea, cramps, bloating, gas, and

diarrhea occurring within 4h of consuming milk products

The treatment includes taking a tablet of lactase enzyme with a meal

The lactase digests the lactose in the food A special lactose free diet may be necessary

© 2008 Paul Billiet ODWS

Source

Lactase enzyme (-galactosidase) is extracted from fungi such as Aspergillus oryzae

http://www.biologie.uni-regensburg.de/

http://biotech.nikkeibp.co.jp/MUSEUM/3.html

© 2008 Paul Billiet ODWS

ReactionSubstrate: Lactose

Lactose + H2O-galactosidase

Glucose + Galactose

This is a hydrolysis reaction

© 2008 Paul Billiet ODWS

Advantages Lactose intolerant patients can

digest their food Lactose free products can be

prepared for special diets Lactase is used to hydrolyse

lactose in ice cream into glucose and galactose to give it a sweeter flavour

Stoney Creek Dairy

© 2008 Paul Billiet ODWS