Hemocyanins.com: Biochemical products for Cell Biology and Cancer Research

Hemocyanins are multisubunit proteins with an oxygen transport function, similar to Hemoglobin. The main difference between these two respiratory pigment molecules is that hemoglobin is an iron-based molecule whereas hemocyanin is based on copper. When deoxygenated, hemocyanin is colorless; when carrying oxygen, it is a pale blue color. It is this pale blue, or cyan, color that gives the pigment its name.

Hemocyanins are found in arthropods (crustaceans like shrimp, crabs, lobsters),insects and mollusks (limpets, clams, oysters, snails, abalone, slugs, squid, and octopus. Compared to hemoglobin, hemocyanin is a rather poor respiratory pigment. It is not as effective as hemoglobin at binding oxygen molecules at low concentrations of oxygen. However hemocyanins have found a very important place in advancing scientific research.

Keyhole limpet (Megathura crenulata) hemocyanin (KLH) is widely used as an immune system stimulant in the generation of antibodies for research and diagnostic purposes. Antibodies to small peptides or haptens are typically produced by conjugating them to large carrier proteins such as KLH. The conjugate is used to immunize an appropriate animal host species such as mouse, rabbit or goat. The host will produce antibodies against the peptide/hapten as well as to the KLH.

KLH has several desirable properties which makes it a good choice as a carrier protein. It has a greater immunostimulatory capacity compared to other commonly used carrier proteins such as ovalbumin (OVA) and bovine serum albumin (BSA). KLH is a large protein with numerous primary amines for coupling peptides and haptens and it is soluble in aqueous solutions.

KLH is also used as a part of a vaccine preparation given to some patients to help them respond to cancer. The vaccine stimulates antibody production against specific tumors. A standard scenario consists of conjugating peptide with an identical amino acid sequence of a tumor-specific mutated protein. KLH is a powerful immune modulator and assists the patients immune system in producing antibodies against the mutated peptide. These antibodies also bind to the mutated protein on the tumor cells causing them to be recognized as foreign to the body and subsequently destroyed.