KX Modifier - SPECIFIC REQUIRED DOCUMENTATION ON FILE. KX -- SPECIFIC REQUIRED DOCUMENTATION ON FILE. (EFFECTIVE DATE 7/1/2002) This modifier may be used to indicate that specific required documentation is on file in the patient's medical record. Documentation must be submitted upon request.
Proteins are made of amino acids hooked end-to-end like beads on a necklace. To simulate. a protein, you will make a model of your protein using a long chenille stem (the fuzzy. covered wire) and colored beads.
The Primary Structure of Proteins. The primary structure of a protein is nothing more than the sequence of amino acids, read off one at a time, as if printed on ticker-tape. Insulin obtained from cows, for example, consists of two chains (A and B) with the primary structures shown in the figure below.