W ITH increasing use of tests of the prothrombin concentration as an aid in the diagnosis of diseases of the liver and as a guide in vitamin K and dicumarol therapy,’6 it is imperative that the determinations be accurate. There are many ways of measuring the prothrombin concentration and each admits of numerous sources of error. Even when the most careful technic is practiced, appreciable error...

Although considerable progress has been achieved in the study of the coagulation of plasma by staphylocoagulase, the precise identity of the coagulase-reacting factor (CRF) has remained in doubt. The claims linking CRF with various factors involved in the dotting of blood have been recently summarized elsewhere (1). Questions pertaining to the possible relation of CRF to prothrombin have remain...

Since the discovery (Soulier and Gueguen, 1947) that phenylindanedione (P.I.D.) was an anticoagulant which effectively altered the one-stage prothrombin time it has been used extensively in the treatment of cases of thrombosis (Blaustein, 1950; Blaustein, Shnayerson, and Wallach, 1953; Dennis, Coon, Hodgson, and Duff, 1952; Toohey, 1953). Clinically it appears to produce the same effect as dico...

We have investigated the pathway of prothrombin activation in blood and plasma. By means of a rapid purification procedure involving chromatography on DEAE-cellulose and hydroxyapatite, we demonstrated that the major prothrombin fragment in serum is that representing the amino-terminal half of prothrombin (i.e. F1-2). The F1-2 isolated was characterized by its size, amino acid and antigenic com...

Vitamin K is a substrate for the enzyme catalyzing the carboxylation of specific glutamyl residues to y-carboxyglutamy1 residues in hepatic precursors of a limited number of plasma proteins, including prothrombin. The y-carboxylation of these proteins can be blocked by the anticoagulant warfarin; and in the bovine and human, warfarin treatment results in the secretion of under-y-carboxylated fo...

The pumpkin is an important kitchen garden crop with very high nutritional value and long lifetime for storage and lot of fiber that acts as one of the best preventive factors from morbid obesity, hypertension, and cardiac diseases. As pretreatment for dehydration, osmotic dehydration creates maximum possible quality in the product by transfer of water outside the tissue of the nutrient. In thi...

S TUDIES of the chemical nature of prothrombin have indicated a glycoprotein structure.2 Data obtained on purified bovine prothrombin have shown the reducing sugar content to be approximately 5 per cent, based on a reference standard of galactose and mannose.35 Laki et al.5 reported a value of 6.5 per cent in terms of glucose, and 1.6 to 1.7 per cent hexosamine. Alexander6 and colleagues observ...

The mechanism by which thrombin and prothrombin control neurite retraction was studied in Ad12E1HER10 human neuroepithelial cells. Morphological changes in differentiated cells were apparent within minutes of the addition of very low concentrations of thrombin (3 pM). Higher concentrations (2 nM) of prothrombin were required to elicit a similar response. Doses of thrombin and prothrombin suffic...

The amino acid sequence of the nonthrombin half of human prothrombin is presented. Prothrombin fragment 1 has 155 amino acid residues as compared with 156 for the bovine equivalent. Ten gamma-carboxyglutamic acid residues are at the same location in each species. Human prothrombin fragment 2 contains 118 amino acid residues, as does the similar bovine fragment. Comparing bovine and human prothr...