Problem 39
Consider the peptides Gly Pro Ser Glu-Thr (open chain) and Gly-Pro-Ser Glu-Thr with a peptide bond linking the threonine and the glycine. Are these peptides chemically the same?
Problem 43
Suggest a reason (or reasons) why amino acids polymerize to form proteins that have comparatively few covalent crosslinks in the polypeptide chain.
Problem 44
Suggest the effect on the structure of peptides if the peptide group were not planar.
Problem 45
Speculate on the properties of proteins and peptides if none of the common amino acids contained sulfur.
Problem 48
How do the peptide hormones oxytocin and vasopressin differ in function?
Problem 50
Is it possible to form cyclic peptides without bonds between side chains of the component amino acids?
Problem 54
Imagine we identify a gene that is directly responsible for the effects of vasopressin on male mammals, including humans-we will call it trust \(1-\) that leads to the production of a vasopressin receptor in the brain, which we will call TRUST1. There are different versions of trust 1 , all of which lead to different levels of the behavior associated with this neuropeptide on male behavior. Give some examples where it would be a good idea to know a particular male's genotype-that is, which of the trustl genes he has. Give an example of when you think science has gone too far and this information should not be known.
