Spectrophotometric assay for urinary N-acetyl-beta-D-glucosaminidase activity.

1981 ◽  
Vol 27 (7) ◽  
pp. 1180-1185 ◽  
Author(s):  
E Horak ◽  
S M Hopfer ◽  
F W Sunderman
Keyword(s):  
Renal Insufficiency ◽  
Coefficient Of Variation ◽  
Gel Filtration ◽  
Nickel Chloride ◽  
Spectrophotometric Assay ◽  
Enzymic Hydrolysis ◽  
Experimental Induction ◽  
Hydrolysis Of ◽  
Urine Specimens ◽  
Healthy Persons

Abstract An improved assay for N-acetyl-beta-D-glucosaminidase activity in urine is described that involves (a) gel filtration to separate the enzyme from inhibitors in urine, (b) enzymic hydrolysis of p-nitrophenyl-N-acetyl-beta-D-glucosaminide at pH 4.4, and (c) spectrophotometry of the liberated p-nitrophenylate. Measurements of activity of the enzyme in 58 urine specimens correlated closely (r = 0.9998) with results by an established procedure. The within-run coefficient of variation (CV) was 3.7%; the between-run CV averaged 6.8%. Reference values for the activity were established by assays of urine specimens from 135 healthy persons, age two weeks to 52 years. Efficacy of the assay for detection of nephrotoxicity was demonstrated in rats after experimental induction of reversible renal insufficiency by intraperitoneal injection of nickel chloride. Clinical application of the assay in approximately 1000 patients corroborated its utility for detection and monitoring of renal disorders.

THE HYDROLYSIS OF CONJUGATED OESTRONE, OESTRADIOL-17β AND OESTRIOL IN HUMAN URINE

1958 ◽  
Vol 17 (4) ◽  
pp. 411-424 ◽  
Author(s):  
J. B. BROWN ◽  
H. A. F. BLAIR
Keyword(s):  
Hydrochloric Acid ◽  
Acid Hydrolysis ◽  
Human Urine ◽  
Major Error ◽  
Enzymic Hydrolysis ◽  
Patella Vulgata ◽  
Pregnancy Urine ◽  
Hydrolysis Of ◽  
Urine Specimens

SUMMARY The hydrolysis of the conjugates of oestrone, oestradiol-17β and oestriol present in human urine has been investigated using acids and the enzymes β-glucuronidase and phenol sulphatase derived from Patella vulgata. Using acid hydrolysis, maximum yields were obtained from the majority of urines by boiling 60 min with 15 vol. % concentrated hydrochloric acid. Under these conditions losses amounting to approx. 20% of the oestrogens present occur in concentrated urine specimens. These losses can be diminished by diluting the urine with water before hydrolysis. Using enzymic hydrolysis, maximum yields were obtained by incubating the urine for 96 hr at 37° C and pH 4·7 with approx. 600 u./ml. β-glucuronidase. When allowance was made for the losses which occur during acid hydrolysis, the yields from pregnancy and non-pregnancy urine were approximately the same by the two hydrolytic procedures. From this, it is inferred that no unknown major error exists in either procedure.

Chemical changes in ultra-heat-treated milk during storage: II. Lactuloselysine and fructoselysine formation by the maillard reaction

1977 ◽  
Vol 44 (2) ◽  
pp. 267-275 ◽  
Author(s):  
A. B. Möller ◽  
A. T. Andrews ◽  
G. C. Cheeseman
Keyword(s):  
Amino Acid ◽  
Maillard Reaction ◽  
Amino Acid Analysis ◽  
Gel Filtration ◽  
Enzymic Hydrolysis ◽  
Preparative Scale ◽  
Uht Milk ◽  
Heat Treated ◽  
Lysine Residues ◽  
Hydrolysis Of

SummaryLactuloselysine (ε-N-deoxylactulosyl-L-lysine) and fructoselysine (ε-N-deoxyfructosyl-L-lysine), formed by Maillard reaction, were identified in enzymic hydrolysates of casein from stored ultra-heat-treated (UHT) milk. Furosine (ε-N-(2-furoylmethyl-L-lysine) and pyridosine (ε-(3-hydroxy-4-oxo-6-methyl-1-pyridinyl)-L-norleucine) were identified in the corresponding acid hydrolysates. Enzymic hydrolysis of the caseins, gel filtration and preparative scale amino acid analysis were used to isolate the compounds which were then identified by reference to synthesized authentic compounds. Lactuloselysine formation was extensive and involved 10–30% of lysine residues in UHT milks stored at 30–37 °C for 6 months to 3 years. Fructoselysine concentration was generally about 10% of the lactuloselysine concentration.

scholarly journals A spectrophotometric assay of β-lactamase action on penicillins

1974 ◽  
Vol 139 (3) ◽  
pp. 789-790 ◽  
Author(s):  
Stephen G. Waley
Keyword(s):  
Spectrophotometric Assay ◽  
New Method ◽  
Enzymic Hydrolysis ◽  
Lactam Ring ◽  
Hydrolysis Of

A new method for measuring the enzymic hydrolysis of the β-lactam ring in penicillins is described. The change in extinction in the u.v. region is determined. The method is sensitive (50μm-benzylpenicillin can be used) and convenient.

Variation in Quantity of Methanol Recovered from Raisins

1963 ◽  
Vol 46 (2) ◽  
pp. 341-343
Author(s):  
M Alice Brown ◽  
James R Woodward ◽  
Floyd DeEds
Keyword(s):  
Methyl Ester ◽  
Esterase Activity ◽  
Enzymic Hydrolysis ◽  
Methanol Content ◽  
Naturally Occurring ◽  
Pectin Esterase ◽  
Hydrolysis Of

Abstract The amount of naturally occurring methanol in fruit must be known so that the quantity left as fumigation residue can be determined. In a study of methanol content of raisins, which had given inconsistent results, the raisins were subjected to different conditions of treatment immediately prior to methanol determination. Conditions that favored pectin esterase activity gave higher values for methanol content than conditions known to inactivate enzymes. Evidence was also obtained that both chemical and enzymic hydrolysis of methyl ester groups of pectic materials occur during analysis.

scholarly journals Permeability of muscle capillaries to small heme-peptides. Evidence for the existence of patent transendothelial channels.

1975 ◽  
Vol 64 (3) ◽  
pp. 586-607 ◽  
Author(s):  
N Simionescu ◽  
M Siminoescu ◽  
G E Palade
Keyword(s):  
Plasma Proteins ◽  
Intercellular Junctions ◽  
Rat Diaphragm ◽  
Enzymic Hydrolysis ◽  
Graphic Analysis ◽  
Heme Peptides ◽  
Future Work ◽  
Hydrolysis Of ◽  
Muscle Capillaries

Two heme-peptides (HP) of about 20-A diameter (heme-undecapeptide [H11P], mol wt approximately 1900 and heme-octapeptide [H8P], mol wt approximately 1550), obtained by enzymic hydrolysis of cytochrome c, were sued as probe molecules in muscle capillaries (rat diaphragm). They were localized in situ by a perixidase reaction, enhanced by the addition of imidazole to the incubation medium. Chromatography of plasma samples showed that HPs circulate predominantly as monomers for the duration of the experiments and are bound by aldehyde fixatives to plasma proteins to the extent of approximately 50% (H8P) to approximately 95% (H11P). Both tracers cross the endothelium primarily via plasmalemmal vesicles which become progressively labeled (by reaction product) from the blood front to the tissue front of the endothelium, in three successive resolvable phases. By the end of each phase the extent of labeling reaches greater than 90% of the corresponding vesicle population. Labeled vesicles appear as either isolated units or chains which form patent channels across the endothelium. The patency of these channels was checked by specimen tilting and graphic analysis of their images. No evidence was found for early or preferential marking of the intercellular junctions and spaces by reaction product. It is concluded that the channels are the most likely candidate for structural equivalents of the small pores of the capillary wall since they are continuous, water-filled passages, and are provided with one or more strictures of less than 100 A. Their frequency remains to be established by future work.

Investigation of the products of an enzymic hydrolysis of collagens

Biochemistry ◽  
1969 ◽  
Vol 8 (12) ◽  
pp. 4716-4723 ◽  
Author(s):  
Howard B. Bensusan
Keyword(s):  
Enzymic Hydrolysis ◽  
Hydrolysis Of

scholarly journals Constancy of the optimum temperature of an enzyme under varying concentrations of substrate and of enzyme

1914 ◽  
Vol 88 (602) ◽  
pp. 258-262
Keyword(s):  
Experimental Evidence ◽  
Aspergillus Oryzae ◽  
Hydrolytic Enzyme ◽  
Fixed Duration ◽  
Optimum Temperature ◽  
Enzymic Hydrolysis ◽  
Main Interest ◽  
General Law ◽  
The Moment ◽  
Hydrolysis Of

In a recent paper a new enzymic relation is recorded. For the enzymic hydrolysis of salicin—by the enzyme which Gabriel Bertrand and the author have named salicinase —it is found that, in an action of fixed duration, the temperature of greatest activity of the ferment is always the same, whatever the dilutions of substrate and of enzyme adopted for the determination. In other words, the duration of the action being constant, the optimum tem­perature of the ferment is independent of the concentration both of the substrate and of the enzyme. The observation is suggestive: if true of one enzyme it may be true of all, and possibly becomes the enunciation of a general law. Herein, for the moment, lies its main interest. In the present paper further experimental evidence for this hypothesis in given, in the case of another hydrolytic enzyme, the maltase of Aspergillus oryzæ (taka-diastase).

Covalent attachment of amino acids to casein. 1. Chemical modification and rates of in vitro enzymic hydrolysis of derivatives

1979 ◽  
Vol 27 (5) ◽  
pp. 1098-1104 ◽  
Author(s):  
Antoine J. Puigserver ◽  
Lourminia C. Sen ◽  
Elvira Gonzales-Flores ◽  
Robert E. Feeney ◽  
John R. Whitaker
Keyword(s):  
Amino Acids ◽  
Chemical Modification ◽  
Covalent Attachment ◽  
Enzymic Hydrolysis ◽  
Hydrolysis Of
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