The advent of cell fusion techniques for producing monoclonal antibodies has stimulated world-wide effort in the search for antibodies with specificity for neoplastic cells. In parallel, a number of laboratories have attempted to devise ways of attaching cytotoxic agents to antibodies with the aim of generating potent anticancer agents from monoclonal antibodies that exhibit sufficient specific...

A method is described for isolating lectins in pure form and quantitative yield in a single step by affinity chromatography on aminoethyl polyacrylamide gels containing reductively aminated disaccharide residues. The affinity columns were prepared in two steps: (a) direct reductive amination of the disaccharide and aminoethyl gel with sodium cyanoborohydride in aqueous solution at pH 9; (b) N-a...

In 1943 AMLONG (1) reported an increase in the transpiration of Cooper's Ernite tomato plants grown from seeds that had been soaked for 24 hours in a solution containing 100 mg. of potassium naphalene acetate, 100 mg. of ascorbic acid and 2000 mng. of thiourea per liter of water. Three years later, BROWN (2) investigating the effect of 2,4-Dichlorophenoxyacetic acid (1000 p.p.m.) on the water r...

Microsomal membrane preparations from the developing endosperm of castor bean (Ricinus communis) catalysed the transfer of oleate from [14C]oleoyl-CoA to phosphatidylcholine (PtdCho). In the presence of NADH, radioactive ricinoleate (12-hydroxyoctadec-9-enoate) was synthesized from [14C]oleate, and this was largely recovered in PtdCho and as free fatty acid. The addition of unlabelled ricinoleo...

During the germination of fatty seeds such as the castor bean, a rapid conversion of fat to sugar occurs (2). The fatty acids are probably broken down to acetyl units via P-oxidation (3) ; the discovery of the glyoxylate cycle enzymes (4) in the castor bean endosperm (5) provided a mechanism whereby these acetyl units could be quantitatively converted to malate. Since malate could be viewed as ...

A cDNA encoding the oleate 12-hydroxylase from castor bean (Ricinus communis L.) has previously been shown to direct the synthesis of small amounts of ricinoleic acid (12-hydroxyoctadec-cis-9-enoic acid) in seeds of transgenic tobacco plants. Expression of the cDNA under control of the Brassica napus napin promoter in transgenic Arabidopsis thaliana plants resulted in the accumulation of up to ...

Chromatographic analysis of organelle-associated citrate synthase activity revealed distinct mitochondrial and glyoxysomal forms of the enzyme. The chromatographic elution patterns on hydroxylapatite, carboxymethylcellulose and DEAE-cellulose of citrate synthase from the endosperm of 4.5-day-old castor bean seedlings revealed significant differences for mitochondrial and glyoxysomal activities ...

A technique for the isolation of intact plastids from spinach (Spinacia oleracea) and pea (Pisum sativum) leaves, pea roots and castor bean (Ricinus communis) endosperm is described. This technique involves brief centrifugation of whole homogenates on density gradients. Intact plastids were located in the gradient by assaying for triose phosphate isomerase activity. Contamination of the plastic...

ATP citrate lyase (EC 4.1.3.8) has been found in crude extracts from endosperm tissue of germinating castor bean and shows its maximum activity in 4- to 5-day-old seedlings. A strict requirement for coenzyme A and adenosine 5'-triphosphate was demonstrated. The pH optimum for the reaction is around 7.5. The unstable enzyme can be stabilized by freezing and addition of citrate and glycerol. (-)-...