Blocks calcium currents via interaction with a yet unknown target protein. Has no effect on L-type, T-type, N-type or P/Q-type voltage-gated calcium channels (VGCC). Has no effect on voltage-gated potassium or chloride channels. Blocks non-L-type VGCC calcium currents in mouse duodenal myocytes (IC(50)=0.2 uM). Blocks calcium influx induced by hypoxia/reoxygenation in rat hepatocytes. Homodimer. Contains disulfide bonds which may also be involved in dimerization. Monomer.