심장 및 간의 mitochondria에서 분리한 flavin peptide처럼 riboflavin이 결핍된 그리고 투여된 간에서도 fluorescence excitation spectra의 second peak에 hypsochromic shift현상을 볼 수 있었다. pH가 2-7범위내에서 riboflavin과 liver mitochondrial flavin peptide의 fluorescence는 아무런 영향을 받지 않았으나 heart mitochondrial flavin peptide는 pH에 의한 fluorescence quenching을 나타냈고 그때 $pK_a$ 값은 4.3이었다. 쥐의 간에서 riboflavin의 결핍시 fluorescence excitation spectra의 fluorescence intensity는 riboflavin과 투여시의 fluorescence intensity에 약 50%에 달하였다.
The hypsochromic shift of the second peak of fluorescence excitation wavelength was observed with flavin peptides isolated from heart and liver mitochondria and from whole livers of riboflavin-deficient and riboflavin-supplemented rats. The fluorescence of riboflavin and liver mitochondrial flavin peptide is independent of pH in the range of 2 to 7 but heart mitochondrial flavin peptide shows a pH-dependent fluorescence quenching with $pK_a$ of 4.3. It is noteworthy that the relative fluorescence intensity of each peak of fluorescence excitation spectra of riboflavin-deficient rat liver corresponds to about 50% that of riboflavin-supplemented rat liver.
