ABSTRACT
<p><b>OBJECTIVE</b>To analyze the constituent proteins in donkey hide, the key ingredient for Ejiao, an important traditional Chinese medicine for the blood-related conditions, in hope to eventually decipher the biochemical mechanism behind Ejiao's prominent medicinal efficacy.</p><p><b>METHOD</b>Two methods were employed to extract proteins in donkey skin. One used TriPure isolation reagent to extract the total proteins in donkey skin. Another used 1% sodium dodecyl sulfate (SDS) to heat the sample at 100 degrees C overnight. And then sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and capillary HPLC were used to analyze the component of proteins.</p><p><b>RESULT</b>There are not only collagen alpha1 (I) and collagen alpha2 (I), but also serum albumin in donkey skin. The content is over 25% in total proteins with the method of TriPure isolation reagent. The content of donkey serum albumin is up to 20% with the method of 1% SDS heating. And two bands, molecular weight are nearly 200 kDa,were found on 7.5% SDS-PAGE. Extracted these proteins to analyze with capillary HPLC, they were found to be the complex products of collagen and serum albumin of donkey.</p><p><b>CONCLUSION</b>Donkey serum albumin is a main protein component in the hide, which is a clue to expose is the effect of Ejiao on blood.</p>