THE ISOLATION OF CRYSTALLINE d-UROBILINOGEN

The isolation of crystalline d-urobilinogen.

Until recently there have been only two well recognized members of the urobilinogen group, mesobilirubinogen, the chromogen of i-urobilin,’ and stercobilinogen, the leuco compound of urobilin or stercobilin. While mesobilirubinogen is readily obtained in crystalline form following amalgam reduction of bilirubin or i-urobilin, stercobilinogen has never been crystallized. Stercobilin, however, wa...

Isolation of Crystalline Ricin

A toxic crystalline protein has been isolated from crude extracts of castor bean meal. Ultracentrifuge and electrophoresis tests show the crystalline protein to become fairly homogeneous after three or four crystallizations. This is also confirmed by toxicity measurements. Solubility tests, however, indicate the presence of more than one protein component in the crystalline material, possibly i...

Crystalline D-serine dehydrase.

Studies on the Determination of Bile Pigments. Vi. Urobilinogen in Urine as Urobilinogen-aldehyde.

THE photometric determination of urobilinogen was proposed by Terwen (i) and employs the reaction of native urobilinogen, plus that derived from ferrous hydroxide reduction of urobilin, with Ehrlich’s reagent, p-dimethylaminobenzaldehyde. This basic approach culminated in the “quantitative” and “semiquantitative” methods of Watson (2,3) with minor modifications by various authors (4). Efforts i...

Isolation of a crystalline albumin from milk.

The relationship between proteins from blood serum and milk has been the subject of considerable study, with some contradictory results (1-5). This is especially true of albumins. Application of electrophoretic techniques to the analysis of whey proteins indicated the presence of a small component, consisting of approximately 3 to 5 per cent of the total protein, with the electrophoretic mobili...