Is Latex a Protein?
text excerpted from http://gasnet.med.yale.edu/gta/latex/latex.html
structures from Organic Chemistry by Fox and Whitesell
illustrations by L. Van Warren
- Latex is the milky sap of the commercial rubber tree, Hevea Brasiliensis.
It is a complex intracellular product of a system of cells that synthesise
a polymer (cis-1,4-polyisoprene), which is the main component
of natural rubber.
The polymer cis-1,4-polyisoprene. The repeating subunit is shown
in parenthesis.
2D ChemDraw File,
Chem3D File for molecular
dynamics
- Latex contains hundreds of proteins, including enzymes that are involved
in the biosynthesis of the rubber molecules. Protein fractions in latex are
responsible for the Type I (anaphylactic) allergic
reactions that make latex allergy an important problem in anesthesia.
- Most natural rubber is produced in Africa and South Asia. Trees are tapped
for latex, by cutting a spiral groove in the bark and placing a spout and
collection cup, containing ammonia or some other preservative, at the bottom.
By centrifugation a concentrated product is obtained. Latex is made heat-stable
and elastic by vulcanization (heating in the presence of sulphur). Additional
chemicals, such as accelerators, and antioxidants are added
for strength, stretch and durability. These additives may be responsible for
Type IV (contact dermatitis) allergic reactions.
- Trans-polyisoprene is a harder natural polymer. Gutta-percha
is an example. This material is obtained from a different species of rubber
tree, and is widely used in dentistry.
- Natural rubber is derived from latex, and should be distinguished
from synthetic rubber, derived from petrochemicals. Synthetic rubber
does not contain allergy-inciting plant proteins but is virtually identical
to natural rubber in its physical properties.