Blood, 1960, Vol. 15, No. 5, pp. 778-790.
© 1960 American Society of Hematology, Inc.
Some Biochemical and Electrophoretic Studies on Purified
Prothrombin, Factor VII (Proconvertin)
and Factor X (Stuart)
GARSON H. TISHKOFF 1,
LIBERTO PECHET 1, and
BENJAMIN ALEXANDER 1
1 Medical Research Laboratories of the Yamins Laboratory, Beth Israel Hospital,
and the Department of Medicine, Harvard Medical School, Boston, Mass.
1. Complete separation of prothrombin, factors VII and X has been
achieved by conventional fractionation technic followed by starch gel electrophoresis.
2. The glycoprotein nature of bovine prothrombin has been confirmed.
3. In addition to hexose and hexosamine, substantial quantities of a hitherto
unrecognized constituent, neuraminic acid, have been demonstrated. When
included with the other carbohydrates, the total sugars comprise a substantial fraction of prothrombin.
4. In electrophoretic mobility the preponderance of proteins and total
neuraminic acid correlate closely with the biologic prothrombin activity.
5. Scission of neuraminic acid by neuraminidase does not result in destruction of the prothrombin, which can subsequently still be converted to thrombin.
6. Significant quantities of neuraminic acid are also found in preparations
rich in factors VII and X but devoid of prothrombin. These fractions are
relatively low in protein. Here, too, cleavage of neuraminic acid does not
destroy biologic activity.
7. Treatment with neuraminidase results in some changes in electrophoretic
mobility of some of the protein, resulting in the appearance of a slower
moving protein fraction devoid of biologic activity. The mobility of factor VII
was slightly altered, but that of factor X remained unchanged.
