PH1123 - Proteins & enzymes Flashcards
what is the amino acid general formula? (4)
carbon bonded to:
- H
- NH2
- R
- COOH
what does the R group of an amino acid determine?
- the chemical property of the amino acid
what forms the continuous peptide backbone? (2)
- bonding between carboxylic acid and amino groups of two adjacent amino acids
- peptide/amino bond formed
what functions does the complex structure of proteins allow them to undertake? (5)
- catalysis (proteins that catalyze chemical reactions in the body are known as enzymes)
- storage and transport
- mechanical support and shape
- decoding information and gene expression
- specialist functions (eg immunoglobin - antibodies)
what are zwitterions? (2)
- dipolar (both charges) in one molecule which can also affect the side chain functional groups
- exists when buffered at pH 7 in the human body
what happens to the acidic and basic side chains in zwitterions? (2)
- acidic side chains are deprotonated
- basic side chains are protonated
what are chiral molecules able to do?
- rotate plane polarized light (they are optically active)
what is an enantiomer?
non-superimposable mirror images of one another ie they are chiral
how are different enantiomers of pairs of amino acids described?
- as D or L
what configuration do all naturally occurring amino acids have and except which one? (2)
- L configuration
- except glycine
by convention how should peptides be named?
- N-terminal on the left (amino group) and C-terminal on the right
what are the four chemical steps in lab for peptide synthesis? (4)
- protection
- activation
- coupling
- deprotection
what is protection?
- blocking of the carboxyl and amino groups not involved in the required peptide bond
what is activation?
- activation of the carboxyl group involved in peptide bond formation
what is a poor leaving group?
- hydroxyl (OH)
