Post-synthetic changes in creatine kinase isozymes (EC 2.7.3.2)

Wevers, Ron A.; Delsing, M.; Gebbink, J.A.G. Klein; Soons, J.B.J.

doi:10.1016/0009-8981(78)90388-1

Cited by 72 publications

(11 citation statements)

References 7 publications

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“…Our findings contradict recent data indicating that only one type of the creatine ; kinase-MM and creatine kinase-MB isoenzyme is present in the cytoplasm of the human skeletal and heart m scle cell (21). The reason for this contradiction could be either poor sensitivity of the methods used, or inactivation of creatine kinase isoenzymes, since creatine kinase isoenzymes undergo reversible and irreversible inactivation in response to oxidation and temperature, respectively (22,23).…”

Section: Discussioncontrasting

confidence: 98%

“…The reason for this contradiction could be either poor sensitivity of the methods used, or inactivation of creatine kinase isoenzymes, since creatine kinase isoenzymes undergo reversible and irreversible inactivation in response to oxidation and temperature, respectively (22,23). Using polyacrylamide, some authors were unable to detect m ny forms of creatine kinase in cardiac tissue extracts (21,24). This could be due to the presence of persisting free radicals generated by ammonium persulphate.…”

Section: Discussionmentioning

confidence: 99%

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The Isoelectric Focusing of Creatine Kinase Variants: I. The Heterogeneity of Creatine Kinase in Human Heart Cytosol and Mitochondria

SiragEldin¹,

Gercken²,

Harm³

et al. 1986

Clinical Chemistry and Laboratory Medicine

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|Summary: Creatine kinase isoenzymes in cytosolic and mitochondrial fractions from human cardiac tissues i· were studied by analytical and preparative isoelectric focusing (IEF), electrophoresis and immunoinhibition. ;Analytical IEF on agärose gels revealed many creatine kinase variants in human cardiac cytosol prepared ! by extraction with a hypotonic medium. The bands located at approximately pH 5.5 were shown to contain creatine kinase-MB and minute creatine kinase-BB bands by electrophoresis. Two bands which focused closely together in IEF (pH 6.85-7.0) showed an electrophoretic migration pattern similar to creatine kinase-MM. One of them (IP 6.85) showed a complete Inhibition by anti-creatine kinase-M antibodies, whereas the other showed only 50% Inhibition.Increasing the salt concentration of tris-HCl (0.1 mol/1) in the extraction medium resulted in additional creatine kinase variants, They were characterized by high alkaline isoelectric points and were not inhibited by anti-creatine kinase-M antibodies. These variants corresponded to two cathodic bands in electrophoresis. iThe treatment of washed mitochondria with phosphate buffer resulted in a release of mitochondrial variants with differestt isoelectric points, äs shown by analytical IEF in agärose gels. l The saine pattern was pbtained by using preparative IEF. Variants with high alkaline isoelectric points gave rise,to two cathodic bands üpon electrophoresis. These two bands resembled those present in cytosol after extraction with high salt concentration. No complete Inhibition with anti-creatine kinase-M was observed in l any of the eluates. ! lThe mitochondrial variants exhibited different affinities towards creatine phosphate and ADR Variants with ,;j higher alkaline isoelectric points showed lower Äm-values for these Substrates than those with less alkaline isoelectric points.

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Section: Discussioncontrasting

confidence: 98%

Section: Discussionmentioning

confidence: 99%

The Isoelectric Focusing of Creatine Kinase Variants: I. The Heterogeneity of Creatine Kinase in Human Heart Cytosol and Mitochondria

SiragEldin¹,

Gercken²,

Harm³

et al. 1986

Clinical Chemistry and Laboratory Medicine

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“…All three parameters can be used as an index for the mean age of the CK M-chain in the blood. It is to be expected that the modifying protein also influences the physicochemical characteristics of the CK MB isozyme [2]. Our data show that there are measurable changes in the Michaelis-Menten constants due to changes in the temperature of the assay.…”

Section: Discussionmentioning

confidence: 64%

“…The ageing of the enzyme can be attributed to a modification in the M-chain caused by a serum protein [1,2], for which the name CK conversion factor has been proposed [3]. As the same protein modifies the alpha chain of enolase as well [7], the name modifying protein was introduced by Wevers et al [7], Recently, the modifying protein has been shown to have carboxypeptidase activity [8,9].…”

Section: Introductionmentioning

confidence: 99%

Indices for the age of the creatine kinase M-chain in the blood

Wevers

Hagelauer

Stein

et al. 1985

Clinica Chimica Acta

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SummaryThe apparent activation energy of the CK reaction as well as the Michaelis-Menten constants and the isoelectric point of CK MM can be used as indices for the mean age of the CK M-chain in the blood in vivo and in vitro. Modifications in the CK M-chain take place in vivo in the blood and in vitro in a serum matrix. Gradual increases in the apparent activation energy are also observed both in vivo and in vitro. It is confirmed that the modification in the CK M-chain causes a rise in the apparent activation energy, u.A gradual increase in apparent activation energy, due to the ageing process of the CK M-chain, was observed after myocardial infarction. A significantly increased value for u was observed at the time that total CK activity already had returned to reference values. In spite of the normal CK value, the apparent activation energy still indicated that there had been myocardial damage. The Michaelis-Menten constants for creatine phosphate and ADP are also influenced significantly by the modification in the M-chain. While the apparent activation energy increases, the Michaelis constants decrease in the order MM,, MM,, MM,. The Michaelis-Menten constants for both ADP and CrP can be used as an index for the mean age of the enzyme in the blood.The Michaelis-Menten constants for CrP and ADP show significant variations with the measuring temperature for virtually all CK MM forms.

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“…The existence of three MM-and two MB-fofms can be explained by this modification (21). The existence of three MM-and two MB-fofms can be explained by this modification (21).…”

Section: The Binding Between Cfeätine Kinase-bb Andmentioning

confidence: 92%

Workshop conference report

1983

CCLM

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It was the aim of the workshop to summarize present knowledge of the variant creatine kinases in human blood. Discussion was centered on the nature, measurement, and clinical significance pfthese variants. On the basis of the presented results, the different creatine kinase variants can be classified äs follows: Normal size variants (80000 Daltons)These originale from postsynthetic modifications of the three dimeric isoenzymes creatine kinase-MM, MB or BB. The M subunit can be transformed by a serum constituent and these modifications result in at least three different creatine kinase-MM and two creatine kinase-MB variants, which still show catälytic activity.The mechanism of the postsynthetic alterations of creatine kinase-BB seems to be more complex: In vitro incubation of this isoenzyme even in a non-serum matrix changes its electrophoretic rnobility and decreases activity. In vivo there is evidence that on the one hand intact creatine kinase-BB molecules are directly removed from the circulation. On the other hand, however, inactive creatine kinase-BB-protein is reported to occur in serum. Variants with higher molecular weights (> 200 000 Daltons)These are termed macro creatine kinases.Macro creatine kinase type l comprises the immunoglobulin-bound creatine kinase isoenzyirfcs. Of these immune complexes, IgG-linked creatine kinäse-BB is well known and has been described in detail, whereas the occurrence of creatine kinase-MM-containing macro creatine kinases is still questionable. Macro creatine kinase type l is found in the blood of about 2% of all hospitalized patients. It occurs mainly in elderly women, but it is not known whether it has any special clinical significance.

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Post-synthetic changes in creatine kinase isozymes (EC 2.7.3.2)

Cited by 72 publications

References 7 publications

The Isoelectric Focusing of Creatine Kinase Variants: I. The Heterogeneity of Creatine Kinase in Human Heart Cytosol and Mitochondria

The Isoelectric Focusing of Creatine Kinase Variants: I. The Heterogeneity of Creatine Kinase in Human Heart Cytosol and Mitochondria

Indices for the age of the creatine kinase M-chain in the blood

Workshop conference report

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