Creatine-kinase MM

Human creatine kinase -MM MAK33 IgGl Cardiac disease, mitochondrial disorders, inflammatory myopathies, myasthenia, polymyositis, McArdle s disease, NMJ disorders, muscular dystrophy, ALS, hypo and hyperthyroid disorders, central core disease, acid maltase deficiency, myoglobinuria, rhabdomyolysis, motor neuron diseases, A. thaliana A. thaliana 2S2 seed storage protein SP + 0.02-0.4% TSP of fresh leaf extract (10-12% TSP of intercellular fluid) 52... 

Time-resolved approaches for multi-analyte immunoassays have been described recently. Simultaneous determination of LH, follicle stimulating hormone (FSH), hCG, and prolactin (PRL) in a multisite manual strip format has been reported. 88 Four microtiter wells are attached to a plastic strip, two-by-two and back-to-back, such that the wells can be read on a microtiter plate reader. In a quadruple-label format, the simultaneous quantitative determination of four analytes in dried blood spots can be done using europium, samarium, dysprosium, and terbium. 89 In this approach, thyroid-stimulating hormone, 17-a-hydroxyprogesterone, immunoreactive trypsin, and creatine kinase MM (CK-MM) isoenzyme are determined from dried blood samples spotted on filter paper in a microtiter well coated with a mixture of antibodies. Dissociative fluorescence enhancement of the four ions using cofluorescence-based enhancement solutions enables the time-resolved fluorescence of each ion to be measured through four narrow-band interference filters. 

Vaidya, H. Dietzler, D.N. Leykam, J.R Ladenson, J.H. Purification of five creatine kinase-MM variants from human heart and skeletal muscle. Biochim. Biophys. Acta, 790, 230-237 (1984)... 

Takasawa, T. Onodera, M. Shiokawa, H. Properties of three creatine kinases MM from porcine skeletal muscle. J. Biochem., 93, 389-395 (1983)... 

The procedure can be complemented by measuring the creatine-kinase MM (CK-MM) in the blood serum of the test animals. CK-MM is the muscle-specific enzyme which leaks out of a skeletal muscle if muscle damage has occurred. Determination of CK-MM should be conducted in the blood serum 24 hours after administration. 

A 47-year-old man presented with severe myalgia and a raised creatine kinase MM isoenzyme (from skeletal muscle) while taking salbutamol from a multidose pressurized inhaler (SEDA-21, 182). The MM creatine kinase activity returned to normal when he stopped salbutamol and rested. When salbutamol was taken by inhaler or orally, the enzyme activity rose. When salbutamol was combined with exercise, even higher concentrations of creatine kinase resulted. A muscle biopsy specimen was consistent with a myopathy. 

Abendschein DR, Fontanet HL, Nohara R. Optimized preservation of isoforms of creatine kinase MM isoenzyme in plasma specimens and their rapid quantification by semi-automated chromatofocusing. Clin Chem 1990 36 723-7. 

A Glycophase DEAE-CPG column has been used to resolve arylsulfa-tase isoenzymes in serum and in concentrated urine samples from healthy controls, patients with colorectal cancer, and patients with malignant melanoma (B16). Creatine kinase MM and BB isoenzymes in brain and in muscle extracts have been resolved by anion exchange, but the MB isoenzyme was not detected either because of denaturation in the chromatographic process or because of adsorption to the column (KI8). The MB isoenzyme has been successfully detected on a DEAE-Glyco-phase column in the serum of a patient who had suffered a myocardial... 

The human plasma metallo-protease carboxypeptidase N (CPN, arginine carboxypeptidase, anaphylatoxin inactivator, kininase I, EC 3.4.17.3) catalyzes the release of the basic amino acids lysine and arginine from the C-termini of peptides and proteins such as bradykinin and kallidin [95], the anaphylatoxins C3a, C4a, and C5a [96,97], fibrinopeptides 6A and 6D [98], hexapeptide enkephalins [99], protamine [100], and the creatine kinase MM-isoenzyme [101,102]. Its most likely physiological function is to protect the organism from the actions of potent peptides, which may escape from tissues or be released in the circulation. 

Xu, Y.Y., Pettersson, K., Blomberg,K., Hemmila, I., Mikola, H., and Lovgren, T. (1992) Simultaneous quadruple label fluorometric immunoassay of thyroid stimulating hormone, 17 a hydroxyprogesterone, immunoreactive trypsin, and creatine kinase MM isoenzyme in dried blood spots. Clinical Chemistry, 38, 2038 2043. 

Apple, F. S., Y. HeUsten, and P. M. Clarkson (1988). Early detection of skeletal muscle injury by assay of creatine kinase MM isoforms in serum after acute exercise. Clin Chem 34(6) 1102-1104. 

As an example, consider the separation of the creatine kinase isoenzymes, MM, MB, and BB. Mercer has used classical ion-exchange chromatography (DEAE - Sephadex - A50) for the resolution of these three isoenzymes (44) To speed up the separation and ultimately to allow an automated analysis,... 

Figure 6, High pressure liquid chromatogram of creatine kinase isoenzymes. First peak, MM second peak, BB. Conditions 50 cm X 4.8 mm (i.d.) column with yydac porous layer bead anion exchange mobile phase, step gradient Solvent A, 10 mmol/liter Tris buffer, pH 8.3 solvent B, 10 mmol/liter Tris buffer, pH 7.0,0.5 mol KCl flow rate, 2 ml/min detection, collected fractions assayed (45).

Creatine kinase, creatine kinase myocardial band Creatine kinase (CK) enzymes are found in many isoforms, with varying concentrations depending on the type of tissue. Creatine kinase is a general term used to describe the nonspecific total release of all types of CK, including that found in skeletal muscle (MM), brain (BB) and heart (MB). CK MB is released into the blood from necrotic myocytes in response to infarction and is a useful laboratory test for diagnosing myocardial infarction. If the total CK is elevated, then the relative index (RI), or fraction of the total that is composed of CK MB, is calculated as follows RI = (CK MB/CK total) x 100. An RI greater than 2 is typically diagnostic of infarction. 

The enzyme responsible for this topping-up ATP in active muscle is CK. CK is found in high concentration in muscle cells, both free within the sarcoplasm and also associated with membranes of mitochondria and the sarcoplasmic reticulum. Structurally, creatine kinase is a dimeric enzyme of B and/or M subunits, each of about 40 kDa. Three quaternary structure isoenzyme forms arise CK-MM, CK-BB and CK-MB. The predominant form in all muscles is CK-MM, but cardiac muscle also contains a significant amount of CK-MB and this isoenzyme can be used as a specific marker of myocardial damage (see Case Notes at the end of this chapter). 

This muscle phosphotransferase (EC 2.132) catalyzes the reversible rephosphorylation of ADP to form ATP (/.c., T eq = [ATP][Creatine]/([Creatine phosphate] [ADP]) = 30). In resting muscle, creatine phosphate is synthesized at the expense of abundant stores of ATP intracellular creatine phosphate stores often reach 50-60 mM. If ATP is suddenly depleted by muscle contraction, its product ADP is immediately converted back into ATP by the reverse of the creatine kinase reaction. Depending on the pH at which the enzyme is studied, the kinetic reaction can be either rapid equilibrium random or rapid equilibrium ordered. A-Ethylglycocyamine can also act as a substrate. 

The enzyme creatine kinase (CK) is formed of two subunits that can either be of the brain (B) type or the muscle (M) type, and different combinations of these types lead to isozymes that predominate in the brain (BB), skeletal muscle (MM), and heart muscle (MB). 

George, S. Ishikawa, Y. Perryman, M.B. Roberts, R. Purification and characterization of naturally occurring and in vitro induced multiple forms of MM creatine kinase. J. Biol. Chem., 259, 2667-2674 (1984)... 

Phosphocreatine (Fig. 13-5), also called creatine phosphate, serves as a ready source of phosphoryl groups for the quick synthesis of ATP from ADP. The phosphocreatine (PCr) concentration in skeletal muscle is approximately 30 nra, nearly ten times the concentration of ATP, and in other tissues such as smooth muscle, brain, and kidney [PCr] is 5 to 10 mM. The enzyme creatine kinase catalyzes the reversible reaction... 

Quaternary structure of isoenzymes Many isoenzymes contain different subunits in various combinations. For example, creatine kinase occurs as three isoenzymes. Each isoenzyme is a dimer composed of two polypeptides (called B and M subunits) associated in one of three combinations CK1 = BB, CK2 = MB, and CK3 - MM. Each CK isoenzyme shows a characteristic electrophoretic mobility (see Figure 5.21). 

Correct answer = D. The CK isoenzyme pattern at admission showed elevated MB isozyme, indicating that the patient had experienced a myocardial infarction in the previous 12 to 24 hours. [Note 48 to 64 hours after an infarction, the MB isozyme would have returned to normal values.] On day 2, 12 hours after the cardioconversions, the MB isozyme had decreased, indicating no further damage to the heart. However, the patient showed an increased MM isozyme after cardo-conversion. This suggests damage to muscle, probably a result of the convulsive muscle contractions caused by repeated cardioconversion. Angina is typically the result of transient spasms in the vasculature of the heart, and would not be expected to lead to tissue death that results in elevation in serum creatine kinase. 

Creatine kinase was purified from rabbit muscle by the method of Kuby et al, (4). Rabbit muscle pyruvate kinase was purchased from Boehringer. Porcine muscle adenylate kinase was purchased from Sigma, and was further purified by gel filtration on Sephadex G-50. The enzymes were homogeneous as judged by their specific activities and by their migration as single components in sodium dodecyl sulfate gel electrophoresis. Proton NMR spectra at 250 MHz of 0.5-2.0 mM enzyme sites in 0 solution were obtained with a Bruker WM 250 MHz pulse FT spectrometer at 25°. At least 256 transients were accumulated over 8192 data points using 16 bit A/D conversion. Relaxation rates and histidine pK values were determined by standard NMR methods (5, 6),... 

Creatine kinase (CK) is a dimeric enzyme with two subunits, M (muscle type) and B (brain type). Three isozymes are distinguished CK 1-BB (brain), CK 2-MB (heart), and CK 3-MM (skeletal muscle). The total CK activity found in skeletal muscle is almost entirely of the CK 3 type, that in heart muscle is 15-20% CK 2 and the remainder CK 3, and that in brain is all CK 1. In the human being, the only significant source of blood CK 2 is the heart muscle. Because the intact blood-brain barrier appears to be impermeable to CK, the occurrence of CK 1 in blood is unlikely. The total serum CK activity in healthy individuals is almost exclusively that of CK 3. 

The patient, a 63-year-old Caucasian female, was hospitalized on 4 April 2002 though 10 April 2002 for a non-ST segment elevation myocardial infarction (non-Q-wave MI per chart documentation). She had a negative adenosine stress test after the initial event. Her serum cardiac-specific troponin I (cTnl) concentration 24 hours after her onset of chest pain was 1.4 pg/L (upper limit of normal is 0.3 ng/mL), and her creatine kinase (CK) MB level was 12.5 pg/L (upper limit of normal 6.0 ng/mL). Three days post-event her cTnl level was 0.5 pg/L and her CK-MB level was 4.5 pg/L (Fig. 5-1). MB refers to one of the isoenzyme forms of CK found in serum. The form of the enzyme that occurs in brain (BB) does not usually get past the blood-brain barrier and therefore is not normally present in the serum. The MM and MB forms account for almost all of the CK in serum. Skeletal muscle contains mainly MM, with less than 2% of its CK in the MB form. MM is also the predominant myocardial creatine kinase and MB accounts for 10%-20% of creatine kinase in heart muscle. 

Apple FS, Murakami MM Cardiac troponin and creatine kinase MB monitoring during in-hospital... 

Lin JC,Apple FS, Murakami MM, et al. Rates of positive cardiac troponin I and creatine kinase MB among patients hospitalized for suspected acute coronary syndromes. Clin Chem 50 333-338, 2004. 

Creatine kinase functions as a dimer. The dimer can consist of combinations of two different subunits, M and B. Different cell types produce or express the MM, MB, or BB forms of CK. Although the amino acid composition of the M and B subunit differ, all three dimeric forms can catalyze the reaction described above. Different forms of an enzyme that catalyze the same reaction (such as the MM, MB, and BB forms of CK) are referred to as isoenzymes. 

Urea standard solutions in water 3.57 mM, 8.92 mM, 10.71 mM, and 35.70 mM Creatine kinase assay reagent consisting of ... 

Although it is true that abnormal proteins increase with age, most of them are a result of posttranslational changes. An example is the various isoforms of creatine kinase (CK). Here, the major isoenzyme, CK-MM (isoform CK-33), is normally synthesized in the heart and skeletal muscle. However, after its release into the circulation, carboxypeptidase hydrolyzes the terminal lysine from one of the M-peptides to form CK-32. Subsequent hydrolysis of the terminal lysine from the second M-peptide produces the third isoform, CK-3i (W8). Numerous similar posttranslational proteins are produced. Hence, the presence of abnormal proteins per se does not support this aging theory. 

Adenosine triphosphate creatine A-phosphotransferase (EC 2.7.3.2), also creatine phosphokinase. Creatine kinase is found in muscle and is responsible for the formation of creatine phosphate from creatine and adenosine triphosphate creatine phosphate is a higher energy source for muscle contraction. Creatine kinase is elevated in all forms of muscular dystrophy. Creatine kinase is dimer and is present as isozymes (CK-1, BB CK-2, MB CK-3, MM) and Ck-mt (mitochondrial). Creatine kinase is also used to measure cardiac muscle damage in myocardial infarction. See Bais, R. and Edwards, J.B., Creatine kinase, CRC Crit. Rev. Clin. Lab. ScL 16, 291-355, 1982 McLeish, M.J. and Kenyon, G.L., Relating structure to mechanism in creatine kinase, Crit. Rev. Biochem. Mol. Biol 40, 1-20, 2005. 

Likewise, following the repeated infusion of doses of 1000-2000 mg/kg DCLHb daily for 7 days or of 400 mg/kg every 6h for 3 days, the concentrations of AST, lactate dehydrogenase (LDH) and creatine kinase (CK) were elevated in monkeys. Isoenzyme profiles for CK and LDH revealed predominant increases in the MM form of CK and the LD-5 form of LDH. The MM-CK originates predominantly from skeletal muscle and may also derive from the myocardium however, the MB isoenzyme, which emanates only from myocardium, was not elevated. The elevation of LD-5 was also consistent with a skeletal muscle source. 

---