Fundamentals of Medicinal Chemistry

S

CH 2

CH

COOCH 3

Protein chain of an

anchored protein

Integral proteins forming

Peripheral protein an ion channel

Cholesterol

Peripheral

protein

Non-polar

tails

Polar head

A

phospholi-

pid

molecule

α-Helix

integral

protein

Glycolipid

Glycoprotein

CONH

Figure A3.1 The fluid mosaic model of membranes.Note:Integral proteins either pass right

through or are deeply embedded in the lipid bilayer. Peripheral proteins are attached to the

surface of the lipid bilayer. Anchored proteins are attached to a so called anchor molecule

embedded in the lipid bilayer.

chemicalpumpsin the membrane. The intracellular face of a membrane at rest,

that is not undergoing cellular stimulation, is the negative side of the membrane.

For a membrane at rest the potential difference (resting potential) between the

two faces of the membrane varies from20 to200 mV. However, when the

membrane responds to cellular stimulation stimulation this inside face is

depolarized and becomes positive.

APPENDIX 3 CELL MEMBRANES 245