Amazon has its own walled garden, with its own proprietary format etc.. So this is not possible without further ado.
One possibility is to convert the Kindle e-books into another format using Calibre and DeDRM software and thus remove the encryption. However, I don't know how well this works as I don't buy anything from Amazon. But I have often been able to remove Adobe DRM with it.
Alternatively, just don't buy any Amazon e-books - unfortunately, you're simply locking yourself in.