摘要:

ABSTRACTα‐Amylase inhibitor is presented in maize seeds. It is a protein as indicated by precipitation with ammonium sulfate and trichloroacetic acid, denaturation by heat, digestion with proteases and by dye‐staining.It was purified to homogeneity by ammonium sulfate precipitation and Sephadex G‐75 gel filtration. It had an apparent molecular weight of 29,600 and did not contain any carbohydrate.Its properties differed from those of previously reported α‐amylase inhibitors, since it was active against α‐amylase of maize, produced during germination as well as against Bacillus subtilis α‐amylase.It was also active against α‐amylase from the insects Tribolium castaneum, Sitophilus zeamais and Rhyzopertha dominica, but it was inactive against α‐amylase from human saliva, hog pancreas, Aspergillus oryzae,wheat, rye, barley, triticale, and sorghum.It was stable for 5 min at 96°C at pH 7. Maximal inhibition required at least 10 min of preincubation with the enzyme at pH 6.8 and 257deg;C. Polyacrylamide gel electrophoresis gave three protein bands, but only one was obtained in S.D.

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1981.tb00658.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTStarch levels as well as the phosphorylases and acid phosphatase activity during ripening of the banana fruit was investigated. The concentrations and sequence of appearance of sucrose, glucose and fructose were determined by use of specific enzymatic reactions. During the climacteric period, the phosphatase activity increased while phosphorylase activity, which initially increased before starch transformation began, thereafter decreased in a complex pattern. The starch was transformed into sucrose with later formation of glucose and fructose. Four bands of phosphorylase multiple forms, detected electrophoretically, did not change during ripening. One of them was able to synthesize a branched starch‐using amylose as a primer and glucose 1 ‐phosphate as the substrate. Banana slices were infiltrated with water or solutions of cycloheximide or actinomycin D. Inhibition of phosphatase‐induced activity was recorded only in the cycloheximide group. No change in phosphorylase activity was detected in any of these infiltrated groups. Sucrose production from starch was partially inhibited both by actinomycin D and cycloheximide. The aformentioned results were interpreted as indicating the previous presence of phosphorylase in the preclimacteric phase without new synthesis during ripening. The increase of activity of phosphatase was probably due to ribosomal synthesis rather than to nucleic acid synt

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1981.tb00659.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTMyrosinase (thioglucoside glucohydrolase, EC 3.2.3.1) activity in dehulled seeds ofBrassica napuscultivar Tower, B. campestriscultivar Candle andB. juncea(oriental mustard) was localized by cyto‐chemical and biochemical procedures. It was found to be associated with the plasmalemma (plasma membrane) in the majority of embryonic cells which is contrary to the general belief that myrosinase is found only in a few specialized idioblasts called ‘myrosin cells’. The presence of lead and sulfur in electron‐opaque deposits resulting fromin situmyrosinase activity was confirmed by energy dispersive X‐ray analyses. Association of myrosinase activity with the plasmalemma was also verified by fractionation and biochemical procedures. Although there were indications of some myrosinase activity in aleurone grains (protein bodies), the evidence was inc

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1981.tb00660.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe crude extract of Antarctic krillEuphausia superbacontained high activities of galactomannoglycanase, carboxymethyl cellulase, chitinase, amylase and relatively low activities of agarase, mannanase, kappa‐carrageenanase and pectinase. The extract also showed high activities of β‐D‐fucosidase, β‐D‐glucosidase, β‐D‐galactosidase and relatively low activities of α‐D‐glucosidase, α‐D‐mannosidase, α‐D‐galactosidase, α‐D‐fucosidase and β‐D‐galacturonidase. The sufficiently high activities of carboxymethyl cellulase, galactomanno‐glycanase, chitinase, β‐D‐fucosidase, β‐D‐glucosidase and β‐D‐galactosidase make krill a potential source for futher

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1981.tb00661.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTInitial adjustment of pH of growth medium in the range of 3.0–5.0 was found to be necessary for optimal production of glucoamylase by a newly isolated strain ofAspergillus niger.Optimum temperature of incubation under stationary conditions was found to be 26–28° C, although incubation at higher temperatures viz. 30 and 37° C led to faster fungal growth rate and increased biomass. In complex medium, the optimum glucose and peptone concentrations were 2 and 3% respectively, and the presence of trace elements was found to be essential for maximal enzyme

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1981.tb00662.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY