Science / Biology / Pepsin: An enzyme produced from pepsinogen that initiates protein digestion by breaking down protein into large peptide fragments. An enzyme, produced by the stomach, that chemically breaks down peptide bonds MORE
Science / Biology / Methionine: The amino acid coded for by the initiation codon; all polypeptides begin with methionine, although post-translational reactions may remove it. MORE
Science / Biology / Quaternary Structure: In some proteins, a fourth structural level created by interactions with other proteins. Aspect of protein structure determined by the number and arrangement of polypeptides in a large protein such as MORE