147Zero to Genetic Engineering Hero - Chapter 6 - Processing Enzymes
Chapter 6
Processing Enzymes
In Chapters 4 and 5 you genetically engineered cells
with DNA plasmids that contained two genes, one that
coded for antibiotic resistance, and another to express
a trait such as a chromoprotein (color pigment). The
proteins that resulted from the K12 E. coli cells tran-
scribing and translating the genes had very different
functions:
1.
Chromoprotein (color pigment): This protein’s
primary function is to be colorful. Once the protein
is created, it bumps around the cell and gives the
cell color. The color pigment DNA was initially
derived from a sea creature which benets in some
way from being colorful.
• Antibiotic resistance: This protein’s function is to
catalyze a chemical reaction. The protein created
for chloramphenicol antibiotic resistance is called
chloramphenicol acetyltransferase. The enzyme is
able to bind to the chloramphenicol molecule and
cause a chemical reaction that inactivates chloram-
phenicol and prevents it from being able to harm
the cell.
This chapter focuses on the latter, protein enzymes
that catalyze chemical reactions and how they are
used by scientists and genetic engineers to create
end-products. Steps 1 and 2 of the
Three Steps to
Microfacturing
are used to create proteins from a DNA
sequence (Figure 6-1), and, in many instances, the
protein itself is the end-product. However, in many
other instances, the protein is not the end-product, it
is instead used to catalyze a chemical reaction involv-
ing other molecules which lead to the desired end
product(s). This is what we consider Step 3 of the T
hree
Steps to Microfacturing
: the processing of molecules
using protein enzymes.
To explore the third step of microfacturing, you will
see rst hand in the hands-on exercises how enzymes
can be used to convert one molecule into another.
Using cell extract, you are going to make pure oxygen
using a naturally occurring protein enzyme called
catalase. You are going to complete a set of new genetic
engineering experiments whereby you engineer K12
E. coli cells to express protein enzymes that will help
you generate smells and a new set of colors in a test
tube!
In the Fundamentals section, we are going to dig deeper
into atoms, bonding, how enzymes function and the
underlying chemistry of enzyme processing. We will
then relate this topic back to cell metabolism and
how it relates to “Life”. You will then fully realize that
the trillions of cells that make up you (and E. coli) are
packed full of enzymes, all of which are encoded by
genes stored in your cells’ genome. These enzymes
drive your metabolism, the chemical reactions that
keep you going.
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