Effect of covalently attached methyl deoxycholate on catalytic activity of lactate dehydrogenase

1992 ◽  
Vol 14 (9) ◽  
pp. 823-826
Author(s):  
P. S. Pandey ◽  
A. Sadana
Keyword(s):  
Catalytic Activity ◽  
Lactate Dehydrogenase

Enhancement of the catalytic activity of d-lactate dehydrogenase from Sporolactobacillus laevolacticus by site-directed mutagenesis

2018 ◽  
Vol 133 ◽  
pp. 214-218
Author(s):  
Kento Nakano ◽  
Shoichi Sawada ◽  
Ryosuke Yamada ◽  
Takashi Mimitsuka ◽  
Hiroyasu Ogino
Keyword(s):  
Catalytic Activity ◽  
Lactate Dehydrogenase ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis

Catabolism of plasma enzymes, as studied with 125I-labeled lactate dehydrogenase-1 in the rabbit.

1976 ◽  
Vol 22 (8) ◽  
pp. 1269-1276
Author(s):  
J H Wilkinson ◽  
A R Qureshi
Keyword(s):  
Enzyme Activity ◽  
Small Intestine ◽  
Catalytic Activity ◽  
Lactate Dehydrogenase ◽  
Extracellular Fluid ◽  
Second Phase ◽  
Enzyme Protein ◽  
Plasma Enzymes ◽  
Close Proximity ◽  
Intestinal Contents

Abstract Circulating enzymes may be inactivated in the plasma and the inactive breakdown products may be hydrolyzed in the lumen of the small intestine. Evidence for this mechanism was based upon previous studies with 125I-labeled lactate dehydrogenase-5, and here similar studies with radioiodinated lactate dehydrogenase-1 are reported, to determine whether this isoenzyme is similarly catabolized. The pure rabbit enzyme was labeled with 125I by use of lactoperoxidase and hydrogen peroxide (the labeled enzyme had 80-85% of the original catalytic activity). After its intravenous injection into rabbits, plasma enzyme activity and radioactivity disappeared during the first 4 h at similar fast rates, apparently because of distribution of the injected enzyme throughout the extracellular fluid. During a second phase (30-h), catalytic activity disappeared significantly faster than radioactivity, suggesting inactivation of the enzyme in either the plasma or a compartment in close proximity to it, or both. Enzyme activity then remained constant while plasma radioactivity continued to decrease at a slower, exponential rate, apparently owing to removal of breakdown products. In no case did tissue radioactivity, studied 6 h after injection, approach that of plasma. We therefore conclude that removal of the enzyme protein or its breakdown products is a passive process. Appreciable radioactivity was detected in the intestinal contents, a finding which suggests that removal via the small intestine is an important route for the removal of inactivated enzyme products from the circulation. Less than 3% of the injected radioactivity appeared in the feces during the first three days; urinary excretion accounted for about 67% during the same period, about 60% of which consisted of radio-iodinated amino-acids, the remainder of iodide. Free mono- and di-iodotyrosines were among the products excreted. These appear to originate from absorption of the products of further breakdown of the enzyme molecule in the intestine.

IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C: International Federation of Clinical Chemistry and Laboratory Medicine (IFCC): Scientific Division, Committee on Reference Systems for Enzymes (C-RSE): Part 8. Reference procedure for the measurement of catalytic concentration of α-amylase: [α-Amylase: 1,4-α-D-glucan 4-glucanohydrolase (AMY), EC 3.2.1.1]

2006 ◽  
Vol 44 (9) ◽  
Author(s):  
G. Schumann ◽  
R. Aoki ◽  
C.A. Ferrero ◽  
G. Ehlers ◽  
G. Férard ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Catalytic Activity ◽  
Lactate Dehydrogenase ◽  
Alanine Aminotransferase ◽  
Clinical Chemistry ◽  
Reference Method ◽  
Reference Procedure ◽  
Activity Concentrations ◽  
Primary Reference

AbstractThis paper is the eighth in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C and the certification of reference preparations. Other parts deal with: Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes; Part 2. Reference procedure for the measurement of catalytic concentration of creatine kinase; Part 3. Reference procedure for the measurement of catalytic concentration of lactate dehydrogenase; Part 4. Reference procedure for the measurement of catalytic concentration of alanine aminotransferase Part 5. Reference procedure for the measurement of catalytic concentration of aspartate aminotransferase Part 6. Reference procedure for the measurement of catalytic concentration of γ-glutamyltransferase; Part 7. Certification of four reference materials for the determination of enzymatic activity of γ-glutamyltransferase, lactate dehydrogenase, alanine aminotransferase and creatine kinase at 37°C. The procedure described here is deduced from the previously described 30°C IFCC reference method. Differences are tabulated and commented on.Clin Chem Lab Med 2006;44:1146–55.

Investigation of the conformation of lactate dehydrogenase and of its catalytic activity

1967 ◽  
Vol 132 (2) ◽  
pp. 271-281 ◽  
Author(s):  
I.A. Bolotina ◽  
D.S. Markovich ◽  
M.V. Volkenstein ◽  
P. Zavodzky
Keyword(s):  
Catalytic Activity ◽  
Lactate Dehydrogenase

Rates of disappearance from plasma of enzymes labeled by coupling with a radioactive lodo-ester.

1976 ◽  
Vol 22 (8) ◽  
pp. 1277-1282
Author(s):  
A R Qureshi ◽  
J H Wilkinson
Keyword(s):  
Creatine Kinase ◽  
Catalytic Activity ◽  
Lactate Dehydrogenase ◽  
Propionic Acid ◽  
Free Acid ◽  
Rabbit Muscle ◽  
Analytical Recovery ◽  
Catalytically Active ◽  
Rapid Hydrolysis

Abstract Lactate dehydrogenase-5 and creatine kinase from rabbit muscle were labeled by coupling with N-hydroxysuccinimidyl 3-(4'-hydroxy-[3',5'-125I]diiodophenyl)propionate. After purification, the analytical recovery of catalytically-active labeled enzyme averaged 90% for lactate dehydrogenase, 81% for creatine kinase. The labeled enzymes were injected intravenously into rabbits and disappearance from plasma of catalytic activity and radioactivity was measured. The disappearance curves for lactate dehydrogenase-5 differed considerably from those observed with the enzyme labeled by direct iodination. The discrepancy was due to rapid hydrolysis in vivo of the labeled amide-enzyme linkage, because about 50% of the injected radioactivity appeared in the urine as 125I-labeled 3-(4'-hydroxy-3',5'-diiodophenyl)propionic acid within 4-8 h of injection. Similar outputs were observed after administration of this acid to rabbits. The free acid was also detected in the urines of rabbits within 4-8 h of the intravenous injection of creatine kinase labeled similarly. We conclude that this method of labeling is unsuitable for preparing radioactive enzymes for study of their catabolism.

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