BCHM 307 1st Edition Lecture 4 Outline of Last Lecture I Amino Acid Basics A Amino Acid Structure II Amino Acid Characteristics A Definition of Chiral B Definition of Enantiomers III Amino Acid List and Abbreviations A Amino Acid Groups Outline of Current Lecture I Structures of Nonpolar Amino Acids A Phenylalanine B Tryptophan II Structures of Polar Uncharged Amino Acids A Serine B Threonine C Tyrosine D Cysteine E Asparagine F Glutamine III Structures of Polar Charged Amino Acids A Aspartate B Glutamate C Lysine D Arginine E Histidine Current Lecture Some amino acids and their structures were discussed in the previous lecture This lecture will cover the rest of the 20 amino acids The amino acids are drawn out below with the common groups given as X and the R groups shown The other two nonpolar amino acids are phenylalanine and tryptophan Both are aromatic compounds as there is a 6 member carbon ring attached to the R groups The aromatic ring gives them both the ability to absorb light at 280 nanometers These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute The next group that will be discussed is the polar uncharged amino acids These have groups on them that make them polar in nature The charges cancel each other out so the molecule has no overall net charge Serine is polar due to the alcohol group attached The alcohol group can be modified by biological kinases in the body Threonine has this happen to it as well due to the attached alcohol group Tyrosine has both an aromatic and an alcohol group attached It can absorb light at 280 nanometers It can also be phosphorylated in a posttranslational modification During this process mutations can occur though Tyrosine mutations can lead to different types of cancer Cysteine contains a sulfur hydrogen group This is normally in the reduced form in the cytoplasm The sulfur can make disulfide bonds links in proteins This is a covalent bond and can mimic hormone binding in the cell Asparagine and glutamine are both very similar in structure The final group is the polar charged group which can donate or accept a proton Aspartate and glutamate are both negatively charged Lysine arginine and histidine are all positively charged
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