0000000000291461
AUTHOR
J. Markl
Molecular Structure of the Arthropod Hemocyanins
Hemocyanin is an extracellular, blue protein that occurs in high concentrations in the blood of many arthropods, including spiders, scorpions, horseshoe crabs, crustaceans, and at least two centipedes. Serving as an ### oxygen carrier, it is functionally equivalent to hemoglobin, but performs reversible oxygen binding between two copper ions. Hemocyanin is composed of a number of subunits that assemble in an extremely large macro-molecular entity. These particles, which are similar in size to viruses or ribosomes, exhibit a complex allosteric behavior during oxygen binding. There is growing evidence that this functional plasticity has evolved upon, and answers to, ecophysiological constrain…
Identification of four distinct subunit types in the unique 6 x 6 hemocyanin of the centipede Scutigera coleoptrata.
We isolated 6 x 6 hemocyanin, dissociated it into subunits, and examined it by electron microscopy. The subunits were separated by native polyacrylamide gel electrophoresis (PAGE), sodium dodecyl sulfate PAGE, and crossed immunoelectrophoresis. Single subunits were isolated by gel cutting from native PAGE and identified as hemocyanin by measuring their ultraviolet spectrum. A total of four distinct hemocyanin subunits were identified, and the subunit pattern of the three electrophoresis systems assigned to each other. The relative proportion of subunits a:b:c:d were 2 : 2 :: 1 as determined by densitometry. Presumably, c and d act as linkers between hexamers.