every node have it's own "wallet". each wallet consist of public/private keys, where public key is address. So there is no centralized place where all wallets

every node have it's own "wallet". each wallet consist of public/private keys, where public key is address. So there is no centralized place where all wallets or coins stored. In fact, there is no coins - there is amounts assigned to each address (public key). And the whole bitcoin network is huge transactions book.