Group 1 Biology - Chemistry

Interface

Group 1 Biology - Chemistry

Interface

course make up:

introductory course

emphasizes integration of chemical & biological concepts

life science majors

~100 students

coreq./prereq. General Chemistry

this unit is 2-3 lectures long

students spend 4-6 hours outside work

Background

previous lectures covered: chemical bonding

protein structure/function

previous lectures covered: chemical bonding

protein structure/function

Enzyme Unit

Overall Learning Goal:Understand what characterizes an enzyme and provide relevant biological examples

Overall Learning Goal:Understand what characterizes an enzyme and provide relevant biological examples

Unit outcomesStudents will be able to:

•construct a graph that demonstrates the effect of an enzyme on activation energy

•compare mechanisms of substrate binding

•compare 2 isozymes that have different affinities (=define kinetic terms, analyze and interpret kinetic data)

•describe ways that enzyme activity can be regulated

Sam, Chris, Ping and Kiran were eager to test the function of an enzyme. They

purified an enzyme from living cells and added it to a test tube containing the proper substrate in a buffer. Much to their disappointment, the enzyme

failed to function.

Brainstorm with your neighbors some possible reasons why the

enzyme that they purified failed to function.

Learning Goal Learning Outcome

to recognize that metal ions often play

a critical role in enzyme

structure/function

generate hypotheses related to enzyme

activity during purification

analyze how a specific amino acid binds to a

metal ion in an enzyme

list common metal ions found in enzymes and identify their sources

Metal Ion-Protein Interactions

How might a metal ion affect enzyme function?How might a metal ion affect enzyme function?

NH

CHC

CH2

O

C

O

O

NH

CHC

CH2

O

C

O

O

--

apo Enzyme(no metal bound)

Mg2+

holo Enzyme(has bound metal)

Mg2+-

HN

CH

C H2C

O

C

OO

NH

CH

C

CH2

O

C

O

O

-

N-terminus

C-terminus

Mg2+-

HN

CH

C H2C

O

C

OO

NH

CH

C

CH2

O

C

O

O

-

A) 1 > 2 > 3

B) 2 > 1 > 3

C) 3 > 2 > 1

D) 1 = 2 = 3

E) 2 > 3 > 1

1

-

2

NH

CH

C

H2C

OH2C C O

O

3

NH

CH

C

H2C

O

NH

Rank from highest to lowest the ability of each of these amino acids to replace the circled amino acid in binding to the magnesium ion:

What other metals are important for enzyme structure

and/or function?

From Nelson and Cox “Lehninger:Principles of Biochemistry”, 5th edition

Why are metalloproteins important to you?

http://img.ehowcdn.com/article-page-main/ehow/images/a05/i1/3v/blood-pressure-cuff-bladder_-800x800.jpg

Going further...

Before the next class, address the following questions on an index card:

•What metal is the cofactor for Angiotensin Converting Enzyme (ACE)?

•How could diet affect the function of this enzyme and what could be some health effects?