ABCC6 does not transport vitamin K3-glutathione conjugate from the liver: Relevance to pathomechanisms of pseudoxanthoma elasticum

► The substrate of ABCC6 preventing soft tissue calcification is not known. ► It was proposed that vitamin K3-glutathione conjugate is the physiological substrate. ► We tested VK3GS transport by several assay systems. ► We found that this conjugate is not a substrate of ABCC6. ► Vitamin K3-glutathione conjugate may not prevent pseudoxanthoma-related symptoms.