UT841 purified from sea urchin (Toxopneustes pileolus) venom inhibits time-dependent (45)Ca(2+) uptake in crude synaptosome fraction from chick brain.
To clarify the mechanism by which the toxic abstract from Toxopneustes pileolus inhibits time-dependent (Time-dep.) Ca(2+) uptake in crude synaptosome fraction, the effective component from pedicellarial venom of the sea urchin was purified. The crude extracts were purified by a series of steps including ion exchange (DEAE-sephadex-A25 gel), gel filtration (with Superdex-2000 and Superdex-peptide columns) and reversed-phase chromatography (Sephasil-C18 column). The effective component that inhibited Time-dep. 45Ca(2+) uptake was purified and named UT841. Its IC(50) was determined to be lower than 35ng/ml. UT841 is an acidic protein with an apparent molecular weight of about 18,000. The N-terminal sequence (40 amino acids) was almost identical to that of Contractin A (a protein purified from the same kind of venom which induces smooth muscle contraction). Even though it is unclear whether or not UT841 is Contractin A, Ca(2+) mobilization in nerve cells was shown to be influenced by UT841. This investigation also revealed that a donor of nitric oxide, arachidonic acid and an inhibitor of phospholipase C selectively inhibit Time-dep. (45)Ca(2+) uptake. These results suggest that UT841 purified from sea urchin venom may affect Time-dep. (45)Ca(2+) uptake through the metabolism of some lipids and nitric oxide.
Zhang
Y
Y
Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1, Kowakae, 577-8502, Higashi-Osaka, Japan.
Abe
J
J
Siddiq
A
A
Nakagawa
H
H
Honda
S
S
Wada
T
T
Ichida
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002645:Chickens; D008969:Molecular Sequence Data; D012617:Sea Urchins / Q000472:pathogenicity*; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D014688:Venoms / Q000737:chemistry / Q000633:toxicity*
D014688:Venoms; D002118:Calcium