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At least 19 recordsLinked to original sources
PubMed1978

Diagnostic value for acute myocardial infarction of creatine kinase and lactate dehydrogenase isoenzymes compared with total enzymes. Creatine kinase isoenzyme specificity for myocardial damage.

The diagnostic value of creatine kinase (CK) and lactate dehydrogenase isoenzymes was investigated in a prospective study of 201 patients with suspected acute myocardial infarction (AMI). The isoenzymes were analyzed with a column chromatographic method. The patients' final diagnoses were made according to the WHO criteria without knowledge of the isoenzyme results. The prevalence of AMI was 50%. The diagnoses were predicted with significantly greater reliability with the isoenzyme than with the total enzyme determinations in most of the patients. However, the greater diagnostic reliability had sufficient therapeutic consequence to justify the extra analytical cost only in patients for whom the diagnosis must be based mainly on the enzyme results. The CK isoenzyme specificity for myocardial damage was studied in populations with low prevalence of heart disease. In a group of 39 patients who had elevated total CK due to noncardiac disease there were five with elevated isoenzyme values, but since among 69 young healthy persons none had elevated isoenzymes, this was taken to indicate that the isoenzymes may be leaked into the blood from other organs than the heart.

Acute Disease↗
PubMed1979

[Creatine kinase and creatine isoenzyme activities in newborn. Development of the organ-typical isoenzyme pattern during the fetal period (author's transl)].

The activity of the creatine kinase isoenzyme was measured in the serum of 133 healthy newborn. In contrast to the conditions in the adult, a normal range of 0-45 U/1 was found. No creatine kinase BMB activities were established. The increased creatine kinase-MB activities in newborn could be explained by means of an examination of the creatine kinase isoenzyme pattern in the skeleton muscle of foetuses and newborn. Depending upon the gestation age, creatine kinase-MB activity levels were found amounting to as much as a multiple of ten of the adult levels. Due to the deviation of the creatine kinase isoenzyme distribution in the organ tissue of newborn, identified in this study for the first time, creatine kinase-MB activity seems to be unsuitable as an indicator of myocardial damage during the neonatal period.

Creatine Kinase↗
PubMed1978

Radioimmunoassay of creatine kinase isoenzymes in human serum: isoenzyme MM.

Measurement of the mass concentration of serum enzymes by radioimmunoassay provides direct quantitation of specific isoenzymes and may be less subject to some of the limitations of traditional assay procedures for enzymes. We describe the development of a sensitive and specific radioimmunoassay for the muscle isoenzyme of creatine kinase, CM-MM, in human serum. CK-MM, purified from human skeletal muscle, was used to raise high-titer antisera and for iodination by the Chloramine T method. The radioimmunoassay required 50 microliter of sample, utilized a double-antibody separation method, and was completed in 24 h. Cross reactivity with CK-BB was virtually zero, 3--17% with CK-MB. The mass concentration of CK-MM in the serum of healthy subjects ranged from 36 to 1668 microgram/liter and correlated closely with total CK enzymatic activity. Serum concentrations of CK-MM from casually selected patients correlated less well with total CK enzymatic activity, suggesting the existence of other CK isoenzymes or the presence of inactive forms.

Adult↗
PubMed1978

Radioimmunoassay of creatine kinase isoenzymes in human serum: isoenzyme BB.

We describe a sensitive, specific radioimmunoassay for the BB isoenzyme of creatine kinase (CK-BB) in serum. A sequential saturation assay was used to achieve sufficient sensitivity to detect the isoenzyme in 100-microliter serum samples of all healthy persons and patients tested. Bound and free antigen were separated by a second antibody system. Large excesses of purified isoenzyme MM did not react in the assay. Cross reactivity of two preparations of CK-MB was only 1 to 7+. The 95th percentile of serum CK-BB in 208 healthy adults was 6.2 microgram/liter. Within-assay and between-assay precision ranged from 5.5 to 11.9% and 9.7 to 13.6%, respectively.

Adult↗
PubMed1979

Thin-layer agarose electrophoresis of lactate dehydrogenase isoenzymes in serum: a note on the method of reporting and on the lactate dehydrogenase isoenzyme-1/isoenzyme-2 ratio in acute myocardial infarction.

We assessed the clinical efficacy of a thin-layer agarose electrophoresis assay for lactate dehydrogenase isoenzyme estimation in the diagnosis of acute myocardial infarction. From a population of 228 patients admitted to the Coronary Care Unit with suspected acute myocardial infarction, all 101 positive cases (confirmed by clinical presentation and electrocardiographic changes) were correctly identified with lactate dehydrogenase isoenzyme-1 percentage of total activity above the reference range and with a lactate dehydrogenase isoenzyme-1/isoenzyme-2 ratio of 0.76 or above. This ratio was between 0.45 and 0.74 for 250 healthy subjects. No falsely negative, but 12 falsely positive results were obtained from this Coronary Care Unit population, to give a sensitivity of 100% and a specificity of 90.5% for the ratio test.

Clinical Enzyme Tests↗
PubMed1979

Dual-detector-post-column reactor system for the detection of isoenzymes separated by high-performance liquid chromatography. II. Evaluation and application to lactate dehydrogenase isoenzymes.

We describe the separation of lactate dehydrogenase isoenzymes by high-performance liquid chromatography-anion-exchange columns and their quantitation by a computer-controlled, dual-detector post-column reaction system. The recoveries from the separation column were ca. 90%. The dynamic range of the system was linear over about three orders of magnitude from 3 to 1500 U/l. The coefficient of variation for isoenzyme peak areas was ca. 2%. The method is compared to the classical electrophoresis measurement and shows increased speed, resolution, precision and accuracy.

Chromatography, High Pressure Liquid↗
PubMed1977

Studies on alkaline phosphatase isoenzymes. Relation to gamma-glutamyltransferase and lactate dehydrogenase isoenzymes.

Gamma-Glutamyltransferase (GT) and isoenzymes of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) have been studied in 282 cases with increased S-ALP and in 18 chronic alcoholics with normal routine liver tests. There was a high degree of correlation between S-GT and the bile (alpha 1) and liver (alpha 2) fractions of S-ALP. Fractionation of alkaline phosphatases sometimes yielded clinical information, which could not be obtained by determinations of S-ALP and S-GT only. The presence of alpha 1-ALP and increased S-GT appeared to be more sensitive indicators of ethanol-induced liver involvement than other liver tests, including LDH-5/LDH-4 ratios.

Alcoholism↗
PubMed1976

[Isolation and properties of cortisol inducible and cortisol non-inducible isoenzymes of rat liver tyrosine aminotransferase].

Rat liver contains two groups of tyrosine aminotransferase (TAT) isoenzymes; during electrophoresis in agar gel one of the groups moves to the anode and the other--to the catode. Cortisol is shown to induce only the anode isoenzymes of TAT, which were isolated, purified and thoroughly analyzed. The inducible anode isoenzyme of TAT spearated from other proteins is more sensitive to the effect of proteases (trypsin and chymotrypsin) than the catode isoenzyme. Some kinetic parameters of the purified TAT isoenzymes were studied. Both isoenzymes have pH optimum around 7.5; their apparent Km values for tyrosine are also similar. However, the catode isoenzyme of TAT possesses a higher affinity for alpha-ketoglutarate than does the anode isoenzyme. Unlike the latter, the former isoenzyme may use oxaloacetate as an amino group acceptor. Pyridoxal phosphate is firmly bound to the catode isoenzyme and can be readily spearated from the anode isoenzyme during dyalisis. An increased sensitivity of the inducible isoenzyme to proteases is due not only to the possibility of coenzyme dissociation, but also to some specific properties of the apoenzyme. The results obtained support the assumption that a high sensitivity of the inducible isoenzymes to proteases provides for a removal of excessive amounts of the enzymes from the cells under cessation of hormonal induction, thus maintaining enzymatic homostasis in the cell.

Animals↗
PubMed1975

Purification and properties of isoenzymes of cinnamyl-alcohol dehydrogenase from soybean-cell-suspension cultures.

Two isoenzymes of an NADP+ -dependent cinnamyl alcohol dehydrogenase and an NAD+ - dependent aliphatic alcohol dehydrogenase were extracted from cell suspension cultures of soybean (Glycine max L., var. Mandarin) which form lignin during growth. These enzymes could be separated from each other by chromatography on DEAE-cellulose and hydroxyapatite. The cinnamyl alcohol dehydrogenase isoenzymes were partially purified by (NH4)2SO4 fractionation, and column chromatography on DEAE-cellulose, Sephadex G-100, and hydroxyapatite. The molecular weight of the enzymes were estimated by the elution volumes from a Sephadex G-100 column and were found to be about 43,000 (isoenzyme 1) and 69,000 (isoenzyme 2). Maximum rates of reaction were observed in the case of coniferyl alcohol oxidation at pH 9.2 (Isoenzyme 1) and pH 8.8 (isoenzyme 2); in the reverse reaction pH 6.5 was optimal for isoenzyme 2. Whereas isoenzyme 1 is specific for coniferyl alcohol, isoenzyme 2 can also oxidize cinnamyl alcohol and a number of substituted cinnamyl alcohols, Km values for substituted cinnamaldehydes are 3-11 times lower than for the corresponding alcohols. Neither isoenzyme reacted with benzyl alcohol, anisic alcohol or ethanol. Substrate inhibition for the forward and reverse reaction was found with isoenzyme 2 but not with isoenzyme 1. The equilibrium constant was determined to be about 10(9) in favour of coniferaldehyde reduction. The possible role of the cinnamyl alcohol dehydrogenase in lignin biosynthesis is discussed.

Alcohol Oxidoreductases↗
PubMed1978

[Isoenzymes, methodology and clinical significance (author's transl)].

In recent years the determination of serum enzyme activities has played an increasing role in clinical chemical diagnosis. Because the enzyme composition of single organs is qualitatively and, to a certain extent, quantitatively similar, the diagnostic value of enzyme activity determinations is often diminished. Each serum enzyme can be separated into isoenzymes which stem from different organs and make specific organ diagnoses possible. This separation is possible through chemico-physical and immunological methods. Electrophoretic, chromatographic and immunological methods for the determination of creatine phosphokinase isoenzymes the immunological method is superior to the electrophoretic method in precision and accuracy. Artefacts through storage do not occur in the immunological method. New aspects of the clinical value of the determination of isoenzymes of alkaline phosphatase (AP, E.C. 3.1.3.1), creatine phosphokinase (CK, E.C. 2.7.3.2) and lactate dehydrogenase (LDH, E.C. 1.1.1.27) were studied in the following 8 patient groups: 1. The value of AP isoenzymes for determining liver damage due to chronic alcoholism. 2. The distribution of AP isoenzymes in dialysis patients with special regard to the intestinal isoenzyme. 3. The immunological demonstration of carcino-placental antigen of AP in tumours of the lung. 4. The demonstration of intestinal isoenzymes of AP in chylous effusions. 5. The profile of LDH isoenzymes in pulmonary alveolar proteinosis in serum and in lung lavage-fluid. 6. The usefulness of CK-MB isoenzyme as proff of cardiotoxicity of pharmaceuticals. 7. The profile of CK isoenzymes in central and peripheral nervous system diseases, especially the appearance of CK-BB in serum and the behaviour of CK at the blood spinal fluid barrier. 8. The appearance of unusual isoenzyme patterns in newborn infants and in pregnant women in comparison with normal adults. The determination of isoenzymes is of great clinical importance, even if the total serum activity of the particular enzyme is not elevated.

Alkaline Phosphatase↗
PubMed1979

Purification and partial characterization of high and low activity carbonic anhydrase isoenzymes from Malaclemys terrapin centrata.

1. High activity (CA C) and low activity (CA B) carbonic anhydrase isoenzymes have been purified from turtle erythrocytes. 2. The two isoenzymes differed in CO2 hydration specific activity by 36-fold. 3. The low activity isoenzyme contained one half-cystine residue, whereas the high activity isoenzyme contained four half-cystines and required a reducing environment to maintain activity. Both isoenzymes contained zinc. 4. Molecular weights of 28,500 and 30,400 daltons were established for the low and high activity isoenzymes respectively. 5. Both isoenzymes were inhibited by acetazolamide, but only the high activity isoenzyme was inhibited by parachloromercuribenzoate. 6. The low activity isoenzyme was present in the erythrocytes at about 8-10 times the concentration of the high activity isoenzyme. 7. The high activity isoenzyme cross-reacted with antibodies prepared against pure chicken carbonic anhydrase C.

Animals↗