Principles of Biochemistry 4th Edition Horton Test Bank. This is NOT the TEXT BOOK. You are buying TEST BANK for Principles of Biochemistry 4th Edition by Horton. Test Bank comes in a PDF or Word fo rmat and available for download only. Principles of Biochemistry 4th Edition Horton Horton Test Bank with answer keys for the tests question only NO Solutions for Textbook's Question included on this purchase. If you want the Solutions Manual please search on the search box