the procedure was capable of adequately separating authentic hydroxyproline from proline , however , upon rechromatography of the `` '' purified '' '' isotope on an analytic resin it was found that background radioactivity in the hydroxyproline region could not be reduced below approximately 500 parts per 10 ( 6 ) parts of [ 14c ] -proline .
C0020388
e hydroxyproli
C0033382
] -proli