NU FS305 Lecture 6: chapter 6

• School: University of Alberta
• Department: Nutrition and Food Sciences
• Course: NU FS305
• Professor: Donna Vine

Document Summary

Contain carbon, hydrogen, oxygen, nitrogen (some also contain sulphur) 20 different amino acids are used to make proteins. Ionization state of amino acid changes with ph. Ionization state of amino acid dependant on ph. Some non-essential amino acids are required in relatively large amounts during specific physiological states. Phenylalanine precursor to tyrosine, if there is low dietary phenylalanine the body cannot make tyrosine, then pa-tyrosine be(cid:272)o(cid:373)es (cid:858)(cid:272)o(cid:374)ditio(cid:374)al(cid:859) (cid:894)the(cid:374) (cid:449)e (cid:374)eed it i(cid:374) higher amounts) Tryptophan, threonine, valine, arginine (conditional), histidine, lysine, phenylalanine, leucine, These ten valuable amino acids have long preserved life in man. Polypeptide = large number of amino acids (>50 amino acids) Sequence of amino acids joined together, aa sequences determine the type of protein. Weak attraction within chain: h+ on one amino acid attracts o- on nearby amino acids: twist into helix, fold into pleats -> rigidity. Tertiary structure : twist and folds in chain. If the stru(cid:272)ture is(cid:374)(cid:859)t right, the fu(cid:374)(cid:272)tio(cid:374) (cid:449)ill (cid:374)ot (cid:449)ork properly.