A cytosolic sialic acid-specific O-acetyl-esterase was previously described that can remove O-acetyl esters from the 9-position of sialic acids. We show that rat liver Golgi vesicles contain a distinct sialic acid-esterase located within the lumen of the same vesicles that add O-acetyl esters to sialic acids. Studies of a retinoblastoma cell line genetically deficient in the cytosolic enzyme al...

For many decades, Botswana has been engaged in various malaria control activities that involved programmes that focused on the elimination of the malaria vector Anopheles ara‐ biensis, by using DDT and pyrethroids. Despite the numerous and continuous application of these insecticides, studies have shown that there is susceptibility of this vector to DDT and pyrethroids in Botswana. Natural inse...

rather than to cause the absence of the wild-type enzyme. It is of interest that in both of these cases hybrid enzymes are formed in heterozygotes. Dimerization which has been proposed as the basis for hybrid vigor' may be a common feature of maize enzymes. Summary.-Two alleles of the E3 gene in maize specify electrophoretically separable esterases. As is the case with the pH 7.5 esterases form...

The activity of eleven enzymes involved in development, ageing and in metabolism of xenobiotics in insects, was investigated under the influence of 2,4-D (2,4-Dichlorophenoxyacetic acid), in the mustard aphid, Lipaphis erysimi (Kaltenbach) (Rhynchota Aphididae), after treating the 2 instar nymphs for 13, 25 and 37 h. Studies of two hydrolases and one group transfer enzyme revealed significant e...

The stability of two thermophilic esterases, AFEST from Archaeoglobus fulgidus and EST2 from Alicyclobacillus acidocaldarius, against the denaturing action of urea and guanidine hydrochloride has been investigated by means of steady-state fluorescence and circular dichroism measurements. Experimental results indicate that the two enzymes, even though very resistant to temperature and urea, show...

The evidence for and against the esterase and dehydrogenase active sites of aldehyde dehydrogenase being topologically distinct is examined. It is found that all the evidence (including all that previously amassed by others in favour of distinct binding domains) is actually consistent with, and in favour of, a single type of catalytic site having both activities. The existence of separate high-...

The esterase profiles of 9 strains of Mortierella ramanniana grown on glucose and olive-oil media were determined by starch-gel electrophoresis. The enzymes produced on the oil medium were in most instances produced also on the glucose medium, but on the latter some additional esterase components were produced. The esterase patterns of the different strains varied widely; only one esterase was ...