Correlation Between Various Proteins of Bovine Snout Epidermis*

Abstract

Summary.— A comparison is made of several properties of urea‐extractable proteins which were isolated from mammalian epidermis. A 6 mol/l urea solution extracts from epidermis at least 3 proteins which are precipitated maximally at pH 6·3, 5·5 and 4·5. The urea 4·5 and 5·5 proteins are soluble in water at pH 7·5 to 8·5. The urea 6·3 proteins were rather insoluble in the absence of urea, but were partially solubilized by 0·05 N NaOH to yield protein which precipitated maximally at pH 5·5, the alkali‐soluble 5·5 protein. Also, the —S—S— bonds of the urea 6·3 proteins were reduced with Clelands reagent (dithiothreitol) and the resultant free‐SH groups were reacted with iodoacetate to yield soluble‐ and insoluble‐S‐carboxymethyl derivatives of these proteins. The urea 6·3 and alkali‐soluble 5·5 proteins have molecular weights exceeding 20 × 106, whereas the S‐carboxymethyl proteins have a molecular weight of 2·2 × 105. The urea 5·5 protein extracted from epidermis at room temperature, and a portion of the urea 5·5 protein extracted at 0°C, have a molecular weight of 5·0 × 104. With antisera prepared in rabbits against the urea 5·5 and 6·3 proteins, the following proteins were found to have common antigenic determinants: urea 4·5, 5·5 and 6·3 proteins, alkali‐soluble 5·5 protein, and the S‐carboxymethyl‐soluble proteins.

On the relationship between the urea-soluble and citric acid-soluble proteins of bovine snout epidermis

“…The S-carboxymethyl derivatives of prekeratin (CM-derivatives) were prepared from 80 or 320 mg of prekeratin (Carruthers & Bhattacharya, 1972). The S-carboxymethyl derivatives of prekeratin (CM-derivatives) were prepared from 80 or 320 mg of prekeratin (Carruthers & Bhattacharya, 1972).…”

“…Prekeratin was trypsinized for 30 and 60 min, and the resulting solutions were dialysed against BBS. t From Carruthers & Bhattacharya (1972). The elution pattern of such a sample, which was trypsinized for 60 min, is shown in Fig.…”

“…Previous experiments showed that the urea-extracted BNE 63, 5-5, and 4'5 proteins developed prccipitin bands of identity with antisera raised against the 63 and 5-5 urea proteins (Carruthers & Bhattacharya, 1972). Previous experiments showed that the urea-extracted BNE 63, 5-5, and 4'5 proteins developed prccipitin bands of identity with antisera raised against the 63 and 5-5 urea proteins (Carruthers & Bhattacharya, 1972).…”

“…at pH 6-3 and 55 (herein called the urea 6-3 and 55 proteins) and were used with the various urea proteins and prckeratin derivatives for immunodiffusion in agar as described before (Carruthers, 1972). Titres of these antisera were determined essentially by the radial immunodiffusion procedure of Masseyeff & Zisswiller (1969).…”

Differences in the Urea-Extracted or Fibrous Proteins of Mouse Epidermis at Various Stages of Malignant Transformation

“…Gel filtration was carried out with Sepharose 4B in conventional columns, essentially in the same way as indicated previously [8], Prior to gel filtration the various urea proteins were thoroughly dialyzed against 0.05 m barbital buffer, pH 8.5, containing 0.1 m NaCl. or in 0.05 m borate buffer, pH 8.5, containing 0.1 m NaCI.…”