scholarly journals The action of progesterone and diethylstilboestrol on the dehydrogenase and esterase activities of a purified aldehyde dehydrogenase from rabbit liver

1977 ◽  
Vol 161 (1) ◽  
pp. 123-130 ◽  
Author(s):  
R J S Julian
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Rabbit Liver ◽  
Polyacrylamide Gels ◽  
Catalytically Active ◽  
Steroid Sensitive ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of ◽  
Esterase Activities

A steroid-sensitive aldehyde dehydrogenase (EC 1.2.1.3) was purified from rabbit liver and is homogeneous by the criterion of electrophoresis in polyacrylamide gels with or without sodium dodecyl sulphate. The enzyme is tetrameric, of subunit mo.wt. 48 300, and contains no tightly bound zinc. The fluorescence of the protein is decreased in the presence of progesterone, which is inhibitory to the reactions catalysed by the enzyme. When NADH is bound to the enzyme, the fluorescence of the coenzyme is augmented to an extent independent of the presence of steroids or acetaldehyde. The purified enzyme catalyses the oxidation of acetaldehyde and glucuronolactone, and the hydrolysis of 4-nitrophenyl acetate. Each of these reactions is inhibited by progesterone in such a manner as to suggest the formation of a catalytically active enzyme-hormone complex. Diethylstilboestrol inhibits the hydrolysis of esters by this enzyme, but stimulates the oxidation of aldehydes, except at low aldehyde concentrations; the ligand is then inhibitory. NADH inhibits the hydrolysis of 4-nitrophenyl acetate by the enzyme in a partially competitive fashion.

scholarly journals Steroid-sensitive Aldehyde Dehydrogenase from Rabbit Liver

1961 ◽  
Vol 236 (4) ◽  
pp. 1032-1037 ◽  
Author(s):  
Elizabeth S. Maxwell ◽  
Yale J. Topper
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Rabbit Liver ◽  
Steroid Sensitive

scholarly journals Properties of pig synovial collagenase

1980 ◽  
Vol 189 (2) ◽  
pp. 349-357 ◽  
Author(s):  
J A Tyler ◽  
T E Cawston
Keyword(s):  
Isoelectric Focusing ◽  
Sodium Dodecyl Sulphate ◽  
Gel Electrophoresis ◽  
Specific Activity ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Type Ii ◽  
Polyacrylamide Gels ◽  
Optimum Ph ◽  
Detectable Difference

1. Properties of a purified chemically activated form of pig synovial collagenase were examined and compared with a spontaneously active form of the enzyme. 2. The active enzyme has a specific activity of 53 000 units (microgram/min)/mg, a mol.wt. of 44 000 (by sodium dodecyl sulphate/polyarcylamide-gel electrophoresis in 2-mercaptoethanol) and pI 5.2 (by isoelectric focusing in polyacrylamide gels). 3. The activity has the characteristics of a metalloproteinase that degrades types I and III soluble or insoluble collagens in preference to type II, at an optimum pH of 6.5-8.5. 4. There is no detectable difference in these properties between the chemically activated and spontaneously active form of collagenase.

scholarly journals p-NN′-phenylenebismaleimide, a specific cross-linking agent for F-actin

1978 ◽  
Vol 175 (3) ◽  
pp. 1023-1032 ◽  
Author(s):  
P Knight ◽  
G Offer
Keyword(s):  
Quantitative Analysis ◽  
Sodium Dodecyl Sulphate ◽  
Actin Filaments ◽  
Sodium Dodecyl ◽  
Cysteine Residue ◽  
Cross Linking ◽  
Maximum Value ◽  
Cross Links ◽  
The Cross ◽  
Hydrolysis Of

Covalent cross-links can be inserted between the subunits of F-actin by using p-NN′-phenylenebismaleimide. Cross-linking reaches its maximum value when one molecule of reagent has reacted with each actin subunit. p-NN′-Phenylenebismaleimide reacts initially with a cysteine residue on one subunit, the slower cross-linking reaction involving a lysine residue on a neighbouring subunit. Hydrolysis of the actin-bound reagent limits the extent of cross-linking. Quantitative analysis of the amounts of cross-linked oligomers seen on polyacrylamide gels containing sodium dodecyl sulphate suggests that neither the binding of the reagent to actin nor the formation of cross-links introduces strain into the structure. The cross-links do not join together different F-actin filaments, and evidence is presented that suggests that the cross-links join subunits of the same long-pitched helix.

scholarly journals Extraction methods and test techniques for detection of vegetable proteins in meat products:I. Qualitative detection of soya derivatives

1976 ◽  
Vol 76 (3) ◽  
pp. 329-336 ◽  
Author(s):  
N. ST G. Hyslop
Keyword(s):  
Sodium Dodecyl Sulphate ◽  
Vegetable Protein ◽  
Sodium Dodecyl ◽  
Meat Products ◽  
Extraction Methods ◽  
Soya Bean ◽  
Animal Origin ◽  
Polyacrylamide Gels ◽  
Migration Rates ◽  
Qualitative Detection

SUMMARYExtracts of 3 soya bean preparations, used commercially in certain countries to replace part of the meat in popular meat products, were made by treatment with (i) sodium dodecyl sulphate, (ii) Triton-X100 or (iii) n–Butanol. Similar extracts were made from beef and pork.All extracts were examined by electrophoretic and immunological techniques. Stained polyacrylamide gels revealed distinctive protein bands after electrophoresis. The migration rates of corresponding bands differed between beef and pork extracts. However, the migration rates of vegetable bands revealed certain similarities, but differed very greatly from those of animal origin. Characteristic fast-migrating S-bands were distinguishable only in extracts of vegetable protein. Immunodiffusion tests, using antisera produced in rabbits against each extract, revealed varying degrees of similarity between extracts of vegetable origin, but the antisera were specific for either vegetable or animal protein.

scholarly journals The action of cytoplasmic aldehyde dehydrogenase on methyl p-nitrophenyl carbonate and p-nitrophenyl dimethylcarbamate

1989 ◽  
Vol 257 (2) ◽  
pp. 579-584 ◽  
Author(s):  
T M Kitson
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Chloral Hydrate ◽  
Slow Release ◽  
Cysteine Residue ◽  
Single Type ◽  
Rate Of Hydrolysis ◽  
Rate Limiting ◽  
Hydrolysis Of ◽  
Enzyme Intermediate ◽  
Esterase Activities

Cytoplasmic aldehyde dehydrogenase catalyses the hydrolysis of methyl p-nitrophenyl (PNP) carbonate at an appreciable rate that is markedly stimualted by NAD+ or NADH. The nuleotides accelerate the rate-limiting hydrolysis of the acyl-enzyme intermediate while slowing the observed burst of p-nitrophenoxide production. With PNP dimethylcarbamate the enzyme catalyses the slow release of approx. 1 molecule of p-nitrophenoxide per tetrameric enzyme molecule; during the reaction the enzyme becomes effectively inactivated, as the rate of hydrolysis of the acyl-enzyme is virtually zero. The presence of NAD+, NADH, propionaldehyde, chloral hydrate, diethylstilboestrol or disulfiram slows the reaction of enzyme with PNP dimethylcarbamate. The reaction appears to be dependent on a group of pKa 7.6, possibly a cysteine residue. The effect of PNP dimethylcarbamate on the dehydrogenase activity of the enzyme is consistent with there being a single type of active site for the enzyme's dehydrogenase and esterase activities. Steric and electronic factors that govern reaction of the enzyme with PNP substrates are discussed.

scholarly journals The effect of cross-links on the mobility of proteins in dodecyl sulphate–polyacrylamide gels

1972 ◽  
Vol 126 (3) ◽  
pp. 553-560 ◽  
Author(s):  
I. P. Griffith
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Cross Linking ◽  
Polyacrylamide Gels ◽  
Gel Method ◽  
Molecular Weights ◽  
Before And After ◽  
Cross Links ◽  
Polyacrylamide Gel Method

The effect of reduction of intramolecular disulphide bridges on the mobility of proteins in 5% (w/v) polyacrylamide gels in the presence of sodium dodecyl sulphate was investigated. A series of polypeptide polymers, containing up to 68 intramolecular disulphide bridges, was prepared by cross-linking proteins of known structure with glutaraldehyde. These model polypeptides were denatured with heat, sodium dodecyl sulphate and urea, and their mobilities in sodium dodecyl sulphate–polyacrylamide gels compared before and after reduction with dithiothreitol. The mobilities of polypeptides containing no cystine were unaffected by reduction. However, reduction generally decreased the mobilities of polypeptides containing cystine; the extent of this decrease depended on the number of cystine residues originally present in the polypeptide polymer, and on the protein from which the latter was derived. In contrast with their higher oligomers, the monomer of lysozyme and the dimer of ribonuclease increased in mobility after reduction. The reduced polypeptide oligomers formed by reaction with glutaraldehyde were generally found to migrate at a rate significantly faster than was expected from their calculated molecular weights. It was concluded that the use of unreduced proteins and protein aggregates for molecular-weight measurements by the sodium dodecyl sulphate–polyacrylamide-gel method may give erroneous estimates of the molecular weight of any protein being investigated.

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