A. L. Gelman

Bio: A. L. Gelman is an academic researcher from Rowett Research Institute. The author has contributed to research in topics: Gluconolactone. The author has an hindex of 2, co-authored 2 publications receiving 214 citations.

Inhibition of glycosidases by aldonolactones of corresponding configuration. The C-4- and C-6-specificity of β-glucosidase and β-galactosidase

Abstract: 1. In barley, beta-glucosidase and beta-galactosidase are separate enzymes. The former also displays beta-d-fucosidase activity. 2. In the limpet, Patella vulgata, beta-glucosidase activity is associated with the beta-d-fucosidase, previously shown to be a separate entity from the beta-galactosidase also present. 3. Almond emulsin presents all three activities as a single enzyme. Each is equally inhibited by glucono-, galactono- and d-fucono-lactone. 4. In rat epididymis, there is no significant beta-glucosidase activity, nor is there appreciable inhibition of the beta-galactosidase and beta-d-fucosidase activities of the preparation by gluconolactone.

Inhibition of glycosidases by aldonolactones of corresponding configuration. The specificity of α-l-arabinosidase

Abstract: 1. The previous study (Conchie, Gelman & Levvy, 1967b) of the specificity of beta-glucosidase, beta-galactosidase and beta-d-fucosidase in barley, limpet, almond emulsin and rat epididymis was extended to alpha-l-arabinosidase. 2. The inhibitory action of l-arabinono-(1-->5)-lactone was tested against all four types of enzyme, and alpha-l-arabinosidase was examined for inhibition by glucono-, galactono- and d-fucono-lactone. 3. In emulsin, the enzyme that hydrolyses beta-glucosides, beta-galactosides and beta-d-fucosides also hydrolyses alpha-l-arabinosides. Rat epididymis resembles emulsin except that, as already noted, it lacks beta-glucosidase activity. 4. In the limpet, alpha-l-arabinosidase activity is associated with the enzyme that hydrolyses beta-glucosides and beta-d-fucosides, and not with the separate beta-galactosidase. 5. The effects of the different lactones on the barley preparation suggest that alpha-l-arabinosidase activity is associated with the beta-galactosidase rather than with the enzyme that hydrolyses beta-glucosides and beta-d-fucosides. Fractionation and heat-inactivation experiments indicate that there is also a separate alpha-l-arabinosidase in the preparation.

The Abnormalities of Lysosomal Enzymes in Mucopolysaccharidoses

Abstract: The activity of acid hydrolases on 13 substrates has been measured in the liver of normal human subjects and of 32 patients with various forms of mucopolysaccharidoses. The most important abnormalities may be summarized as follows: 1 In 3 patients, there was a complete absence of α-fucosidase and an excess of fucose in the mucopolysaccharide fraction. The enzymatic deficiency extended to the brain, lung, kidney and urine. In the liver there was also a large increase in the activity of several acid hydrolases, mostly of the α-galactosidase and of the β-xylosidase. 2 In 5 patients with pseudo-Hurler disease (generalized gangliosidosis), the activity of β-galactosidase, at pH 3.6 was absent and this defect also extended to other tissues. This enzymatic deficiency explains the known accumulation of galactose-rich mucopolysaccharides and of galactosyl-N-acetylgalactosaminyl N-acetyl-neuraminyl)-galactosylceramide (GM1 ganglioside) in the tissues. Several enzymatic activities were greatly elevated, mostly that of α-fucosidase, α-galactosidase and N-acetyl-β-glucosaminidase. 3 In 14 patients with an usual form of Hurler syndrome, the activity of acid β-galactosidase was markedly reduced and this abnormality extended also to the brain and the derm but not to the kidney, spleen and leucocytes. The N-acetyl-β-hexosaminidases, the β-glucuronidase and the α-fucosidase were much more active than normally. 4 In two siblings only, affected by an unusual type of Hurler syndrome, there was a marked elevation of β-galactosidase. The etiological significance of these findings is discussed and a classification of the mucopolysaccharidoses, based on the activity of the lysosomal enzymes in the liver, is proposed.

Control of plant cell enlargement by hydrogen ions.

Abstract: Publisher Summary This chapter discusses the evidence that in Avena coleoptiles and pea stem tissues the hormone auxin induces cell enlargement, by activating proton extrusion, and that the resulting acidification of the wall leads to enzymic cell wall loosening and thus cell enlargement. It emphasizes the point that auxin itself does not act directly on the wall but acts at the cell surface or within the cytoplasm. When a plant cell enlarges, most of the increase in volume is due to the uptake of water into an expanding–centrally located vacuole. The direction of the cell expansion depends on the molecular architecture of the wall and can be primarily in one direction or equally in all directions. Cell enlargement can be initiated in one of the two ways: by an increase in the osmotic concentration of the cell or by an increase in cell wall extensibility (cell wall loosening). In most systems, cell enlargement is initiated by wall loosening. If a section is removed from the elongation zone of a pea stem and placed in water, the cells enlarge, but only at a slow rate. Rapid enlargement can be induced by only four agents: the group of hormones called auxins, hydrogen ions, CO, and the phytotoxin fusicoccin. If hydrogen ions are excreted from auxin-treated Avena coleoptile cells, and if the pH of the wall region falls below 5.8, the walls would undergo cell wall loosening and growth would occur.

Lysosomal enzymes in the acrosome and their possible role in fertilization.

Abstract: Summary. Ram spermatozoa were washed with hypotonic tris-HCl buffer and obtained almost free of seminal plasma and cytoplasmic droplets. Acrosomes were dislodged by incubating the spermatozoa with a cationic detergent (Hyamine 2389). The acrosomal preparation and the buffer washings were examined for the following lysosomal enzymes: acid phosphatase, aryl sulphatase, \g=b\-N-acetylglucosaminidase, phospholipase A and proteases. All enzyme activities were detected, both in washings and in acrosomal preparations. The levels of activity in the latter were much higher than could be expected on the assumption that all activities were due to contamination by washings. Protease activity was greatest at pH 7\m=.\5. After vital staining with Euchrysine 3R, acrosomal fluorescence in ram, bull, boar and human spermatozoa is not very conspicuous. However, acrosomes of guinea-pig, hamster and several rodents show the brilliant orange-red fluorescence typical of lysosomes. As spermatids mature, red-fluorescing granules around the Golgi zone condense to form the red-fluorescent pro-acrosomes. Acid phosphatase was detectable histochemically in granules, pro\x=req-\ acrosomes, acrosomes and the pellets obtained by high-speed centrifugation of acrosomal preparations. At all developmental stages, histochemical tests for bromochloroindoxyl acetate esterase showed that this enzyme was present only in the acrosome. The evidence suggests that the acrosome is a specialized lysosome which evolved to facilitate fertilization in multicellular organisms.