ABSTRACT
A m o n g th e propertie s o f amin o acid s tha t ar e mos t pertinen t t o th e biomedica l
scientist ar e thei r optica l rotations , alread y discussed , w h i c h ar e liste d fo r eac h
amino aci d i n Tabl e 4.1. Not e th e dramati c differences betwee n optica l rotation s
in th e zwitterionic (water ) an d full y protonate d (HC1 ) forms. Further , al l amin o
acids absor b ultraviole t light i n the rang e 190-22 0 n m. Th e C= 0 bond i n carboxyl residues i s largel y responsible . Moreover , aromati c amin o acids , especiall y
tryptophan, absor b in the 260-28 5 nm range . Protei n concentrations i n solution s
are ofte n determine d vi a absorptio n a t 210 o r 280 n m .
