A 100-kDa antigen recognized by a newly prepared monoclonal antibody specific to the vanadocytes of the vanadium-rich ascidian, Ascidia sydneiensis samea, is glycogen phosphorylase

Ascidians have the unusual physiological ability to accumulate high levels of vanadium and reduce it to the +3 oxidation state (V-III) in vanadocytes, the vanadium-containing blood cells. We are characterizing several polypep tides specific to vanadocytes that may participate in this. This study reve aled that a 100-kDa antigen, recognized by a newly prepared monoclonal anti body, S8E4, is exclusively localized in vanadocytes, and identified the ant igen as glycogen phosphorylase (EC 2.4.1.1) by sequencing the encoded cDNA. Since two enzymes, glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-p hosphogluconate dehydrogenase (EC 1.1.1.44), both in the pentose phosphate pathway, have already been identified in vanadocytes, at least three enzyme s involved in carbohydrate metabolism are localized in vanadocytes in huge amounts.