a. VVEIiER 



101 



muscle lactic dehycliogcnase, it bears no great relation to that ol the 

 native protein. Perhaps the most interesting fact about the polariza- 

 tion spectrum ol protein fluorescence is that a resolution of the order 

 of 1 lUfx, as employed in these measurements, was necessary to reveal 

 some of the details present, and that one gathers the impression that 

 by further improvement in resolution and by the use of a continu- 

 ously recording method some more detail could be revealed. The in- 

 terpretation ol the polarization of the fluorescence of proteins from 



POLARIZATION SPECTRA OF BSA & HSA 

 in SO fo Propylene Glycol / Water 



240 250 260 270 280 290 300 3IO 320 



X 



lig. I(>. Polarization spectra of bovine serum albumin and of human serum 



albumin. 



that of the simple derivatives is anything but straightforward. An 

 increase in the ratio p3nr,/p27o should not be taken as proof of an 

 internal transfer of energy among the tryptophan residues, since a 

 high ratio (1.8) is observable in human serum albumin, in which 

 there is only one tryptophan. The effect of pH on bovine serum 

 albumin, already mentioned as indicating that each tryptophan can 

 be quenched independently, is strongly against the occurrence of any 

 transfer between the two tryptophans of this protein; and the same 

 can be said of lysozyme. Nor does the transfer of energy from 

 tryptophan to a imiquely attached substance, as in the case of DPNH 

 and lactic dehydrogenase described by Velick (24a) , constitute 



