The kinetics of dextranase activity were studied using dextran-containing samples of mixed juice taken from mills in Puerto Rico and Jamaica. Mean values of the initial enzyme velocity (V) were 0,063 and 0,173 mg dextran hydrolysed/min/unit enzyme in Puerto Rico and Jamaica respectively. Mean substrate concentrations, expressed as dextran % w/v juice determined by the haze analysis technique, w...

It has long been known that enzymically catalysed synthesis and hydrolysis of cholesterol esters occurs in the presence of certain tissues (Kondo, 1910a, b; Schultz, 1912; Cytronberg, 1912; Gardner & Lander, 1913; Mueller, 1916a, b; Porter, 1916; Nomura, 1924a, b; Shope, 1928; Nedswedski, 1935, 1936; Klein, 1939; Sperry, 1935; Sperry & Stoyanoff, 1937, 1938). The most extensive recent studies, ...

Delory & King (1943) published a comparative study of the hydrolysis by faecal alkaline phosphatase of a series of phosphoric esters and established a correlation between the pK values of their second phosphate dissociations, the optimum pH for the enzymic hydrolysis and the Michaelis constants of the esters. They showed that the more acid this phosphate dissociation, the more alkaline was the ...

Defined radical species generated radiolytically were allowed to attack proteins in solution. The hydroxyl radical (OH.) in the presence of O2 degraded bovine serum albumin (BSA) to specific fragments detectable by SDS/polyacrylamide-gel electrophoresis; fragmentation was not obvious when the products were analysed by h.p.l.c. In the absence of O2 the OH. cross-linked the protein with bonds sta...

The increased turnover of phosphatidylinositol (PtdIns) in response to activation of cell-surface receptors was discovered by Hokin & Hokin (1953). The structures of the so-called polyphosphoinositides, phosphatidylinositol 4-phosphate (Ptdlns4P) and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], were not elucidated until the next decade, but their metabolic importance was suggested by ...

1. The soluble phospholipase D of cabbage was purified by heat treatment, acetone precipitation and electrophoresis on a density gradient of aqueous glycerol. 2. The purified enzyme slowly attacked a lecithin suspension whereas ultrasonically treated lecithin was hydrolysed more rapidly. 3. Diethyl ether stimulated the hydrolysis of both the lecithin suspension and ultrasonically treated lecith...

The spin-labeled cardiolipin 1-(3-sn-phosphatidyl)-3-[1-acyl-2-(16-doxylstearoyl)glycero(3)phosphol]-sn-glycerol has been prepared. The stereoselective synthesis makes use of the monolysocardiolipin 1-(3-sn-phosphatidyl)-3-[1-acyl-2-lyso-sn-glycero(3)phospho]-sn-glycerol, available from the stereospecific hydrolysis of cardiolipin by phospholipase A2 (phosphatide 2-acylhydrolase, EC 3.1.1.4) of...

It is noteworthy that most of the recent observations concerning the structure of ribonucleic acid (1) are in agreement regarding the presence of an as yet unknown labile linkage or linkages in the molecule. The information that has brought the facts to light has been obtained mostly by the use of enzymic methods. By the use of the enzyme ribonuclease, Allen and Eiler (2) have been able to show...