Non-ionic detergents such as polyoxyethylene-octylphenol or -sorbitolester were found to increase activity of horseradish peroxidase due to delay of inactivation in the course of substrate reaction. This rise in activity was investigated using different chromogens and was highest with o-dianisidine. An increasing stability of the enzyme to higher reaction temperatures was observed when detergents were added to the substrate solution, and the action of detergents also is enhanced with increasing reaction temperature and time. Different degrees of activation were found when comparing substrate conversion with and without detergents using free peroxidase (2.7-fold) and conjugated peroxidase bound to the solid phase by antigen antibody reaction (1.8-fold). In enzyme-immunoassay, detection limit and analytical sensitivity can be doubled.

EDTA and EGTA, added to the reaction mixture for the activity determination of creatine kinase, stimulate the activity of creatine kinase to various extents by suppressing the inhibitory effect of Ca2+ ions. The activation effect is highest for isoenzyme BB, less for isoenzyme MB, and lowest for isoenzyme MM.

FEBS LettersVolume 108, Issue 2 p. 469-472 Full-length articleFree Access A fatty acid binding peptide of rat liver cytosol Characterization and origin B. Rüstow, B. Rüstow Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this authorD. Kunze, D. Kunze Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this authorJ. Hodi, J. Hodi Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this authorE. Egger, E. Egger Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this author B. Rüstow, B. Rüstow Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this authorD. Kunze, D. Kunze Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this authorJ. Hodi, J. Hodi Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this authorE. Egger, E. Egger Department of Clinical Biochemistry, Humboldt- University, Bereich Medizin (Charité), Berlin, GDRSearch for more papers by this author First published: December 15, 1979 https://doi.org/10.1016/0014-5793(79)80590-6Citations: 14AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References 1 E.O. Arridsson, J. Polymer Sci., 16, (1968), 4215– 4218. 2 A.A. Spector, K. John, J.E. Fletscher, J. Lipid Res., 10, (1969), 56– 67. 3 A.A. Spector, J. Lipid Res., 16, (1975), 165– 168. 4 G. Fleischner, J. Robbins, J.M. Arias, J. Clin. Invest., 51, (1972), 677– 684. 5 A.J. Levi, Z. Gatmaitau, J.M. Arias, J. Clin. Invest., 48, (1969), 2156– 2167. 6 R.K. Ockner, J.A. Manning, R.B. Poppenhausen, W.K.L. Ho, Science, 177, (1972), 56– 58. 7 S. Mishkin, R. Turcotte, Biochem. Biophys. Res. Commun., 57, (1974), 918– 926. 8 P.J.A. O'Doherty, A. Kuksis, FEBS Lett., 60, (1975), 256– 258. 9 G. Suzue, Y.L. Marcel, Can. J. Biochem., 53, (1975), 804– 809. 10 B. Rüstow, J. Hodi, D. Kunze, E. Egger, FEBS Lett., 95, (1978), 225– 228. 11 G. Fairbanks, T.L. Steck, D.F.H. Wallach, Biochemistry, 10, (1971), 2606– 2617. 12 B.E. Change, B.R. Knowles, J. Lipid Res., 17, (1976), 176– 179. 13 Deutsches Arzneibuch (1968) 7. Auflage, Bd. Diagn. Lab.methoden, Berlin. 14 G. Kurz, K. Wallenfels, U. Bergmeyer Methoden der enz. Analyse (1970), Akademie Verlag Berlin 1241– 1244. 15 C. Cessi, F. Piliego, Biochem. J., 77, (1960), 508– 510. 16 L. Warren, J. Biol. Chem., 234, (1959), 1971– 1976. 17 O.H. Lowry, N.J. Rosebrough, A.L. Farr, R.J. Randall, J. Biol. Chem., 193, (1951), 265– 275. 18 D. Hill, J. Biol. Chem., 243, (1968), 4440– 4448. 19 G. Vaitukaitis, J.B. Robbins, E. Nieschlag, G.T. Ross, J. Clin. Endocrin., 33, (1971), 988– 1002. 20 A.J. Crowle, Immunodiffusion (1961), Academic Press London, New York 21 N. Fournier, M. Geoffroy, J. Deshusses, Biochim. Biophys. Acta, 533, (1978), 457– 461. Citing Literature Volume108, Issue2December 15, 1979Pages 469-472 ReferencesRelatedInformation

The suitability of thirteen commercially available control sera for measuring alkaline phosphatase (EC 3.1.3.1; orthophosphoric acid monoester phosphohydrolase, ALP) activity in human serum was tested. Apart from differences in ALP activity observed in some reconstituted commercial sera, the behaviour of control materials towards experimental variables such as the nature and concentration of the substrate, pH and type of buffer (or PO4-acceptor) together with the composition of the isoenzymes present in human serum highlights the problems and difficulties if commercial materials are to be used as control sera. The half-saturation constants in control sera were in all cases smaller than those of ALP isoenzymes from bone and liver. The shape of substrate activity curves and the pH optimum in most of control sera differed from that of human serum. The discrepant kinetic data of control materials and human serum may mask or suggest changes relevant to commercial quality control serum but not to samples of human serum.

The activity of the creatine kinase isoenzyme BB was determined in the serum of 26 healthy adults and 31 children. The isoenzyme BB could be proved as a normal component in the human serum. In the adults examined, an activity of 0.56 ± 0.16 I.U./l (x ± S.D.) was determined. The activity of creatine kinase isoenzyme BB in the serum does not depend on sex but is subject, however, to a strong age dependence. Only at an age of more than 18 years, isoenzyme BB activities adjust to those of adults.

The stability of isoenzymes of alkaline phosphatase from liver, bones and small intestine was compared after addition to inactivated serum in the buffer systems: glycine, 2-amino-2-methyl-1-propanol, diethanolamine and 2-amino-2-methyl-1,3-propandiol at 37 degrees C. The mentioned isoenzymes were inactivated to different extents in glycine and 2-amino-2-methyl-1-propanol buffers. In diethanolamine and 2-amino-2-methyl-1,3-propandiol buffers sufficient stability of isoenzymes is obtained so that only these buffers are suitable for activity determinations of alkaline phosphatase at 37 degrees C.

In activity determination with addition of pyridoxal 5'-phosphate (P-5-P), aspartate aminotransferase (AST) activity increases by 6.5 U/l and that of alanine aminotransferase (ALT) by 2.5 U/l in the serum of healthy persons. This corresponds to a relative stimulation of initial activity by 37% and 15.2%, respectively. ApoAST activity in patients with chronic liver diseases is not changed as compared with that of healthy persons, the relative stimulation rate, however, is significantly smaller. ApoALT activity and corresponding relative stimulation is significantly greater as compared with healthy persons. In the case of acute viral hepatitis, a decrease of AST and ALT activity is followed by a decrease of apoenzyme activity in the course of disease. Diagnostic evidence of determinations of aminotransferase activities could not be improved by addition of P-5-P).

FEBS LettersVolume 95, Issue 2 p. 225-228 Full-length articleFree Access Specific binding of saturated and unsaturated fatty acids on the ‘Z’-protein of rat liver cytosol B. Rüstow, B. Rüstow Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorJ. Hodi, J. Hodi Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorD. Kunze, D. Kunze Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorG. Reichmann, G. Reichmann Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorE. Egger, E. Egger Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this author B. Rüstow, B. Rüstow Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorJ. Hodi, J. Hodi Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorD. Kunze, D. Kunze Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorG. Reichmann, G. Reichmann Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this authorE. Egger, E. Egger Department of Clinical Biochemistry, Humboldt-University, Bereich Medizin (Charité), Berlin, GermanySearch for more papers by this author First published: November 15, 1978 https://doi.org/10.1016/0014-5793(78)80999-5Citations: 20AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume95, Issue2November 15, 1978Pages 225-228 ReferencesRelatedInformation

Monethanolamine, a frequent impurity of diethanolamine, inhibits the activity of the isoenzymes of alkaline phosphatase to various extents. Isoenzymes from liver and bone, in particular, are strongly inhibited. Inhibition is stronger at lower (25 degrees C) than at higher temperatures (37 degrees C).

FEBS LettersVolume 74, Issue 2 p. 220-224 Full-length articleFree Access Exchange of different phosphatidylcholine molecular species by phospholipid exchange protein of rat liver G. Schulze, G. Schulze Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this authorK. Jung, K. Jung Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this authorD. Kunze, D. Kunze Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this authorE. Egger, E. Egger Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this author G. Schulze, G. Schulze Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this authorK. Jung, K. Jung Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this authorD. Kunze, D. Kunze Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this authorE. Egger, E. Egger Department of Clinical Biochemistry, Charité, Humboldt-University, 104 Berlin, GermanySearch for more papers by this author First published: March 01, 1977 https://doi.org/10.1016/0014-5793(77)80850-8Citations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 K.W.A. Wirtz, D.B. Zilversmit, J. Biol. Chem., 243, (1968), 3596– 3602. 2 K.W.A. Wirtz, H.H. Kamp, Deenen L.L.M. van, Biochim. Biophys. Acta, 274, (1972), 606– 617. 3 C. Ehnholm, D.B. Zilversmit, J. Biol. Chem., 248, (1973), 1719– 1724. 4 H.H. Kamp, K.W.A. Wirtz, Deenen L.L.M. van, Biochim. Biophys. Acta, 318, (1973), 313– 325. 5 den Besselaar A.M.H.P. Van, G.M. Helmkamp, K.W.A. Wirtz, Biochemistry, 14, (1975), 1852– 1858. 6 R.A. Demel, K.W.A. Wirtz, H.H. Kamp, Kessel G. van, Deenen L.L.M. van, Nature New Biol., 246, (1973), 102– 105. 7 W.C. McMurray, R.M.C. Dawson, Biochem. J., 112, (1969), 91– 108. 8 M. Akaijama, T. Sakagami, Biochim. Biophys. Acta, 187, (1969), 105– 112. 9 L.W. Johnson, D.B. Zilversmit, Biochim. Biophys. Acta, 375, (1975), 165– 175. 10 G.M. Helmkamp Jr., M.S. Harvey, K.W.A. Wirtz, Deenen L.L.M. van, J. Biol. Chem., 249, (1974), 6382– 6389. 11 G.M. Helmkamp Jr., S.A. Nelemans, K.W.A. Wirtz, Biochim. Biophys. Acta, 424, (1976), 168– 182. 12 D. Kunze, G. Reichmann, E. Egger, D. Olthoff, K. Döhler, Europ. J. Clin. Invest., 5, (1975), 471– 475. 13 K. Jung, D. Kunze, G. Schulze, E. Egger, Acta Biol. Med. Germ., 34, (1975), 241– 246. 14 W. Liese, K. Jung, W. Kunz, H. David, Acta Biol. Med. Germ., 27, (1971), 477– 498. 15 S. Fleischer, B. Fleischer, R.W. Estabrook M.E. Pullmann Methods in Enzymology 10, (1967), Academic Press New York 412– 413. 16 K.W.A. Wirtz, D.B. Zilversmit, Biochim. Biophys. Acta, 193, (1969), 105– 116. 17 G. Schulze, K. Jung, D. Kunze, E. Egger, Acta Biol. Med. Germ., 35, (1975), 1– 5. 18 D.T. Gordon, R.G. Jensen, Lipids, 7, (1972), 261– 262. 19 H. Hauser, L. Irons, Hoppe-Seyler's Z. Physiol. Chem., 353, (1972), 1579– 1590. 20 G. Rouser, S. Fleischer, R.W. Estabrook M.E. Pullmann Methods in Enzymology 10, (1967), Academic Press New York 404– 405. 21 A.G. Gornall, C.J. Bardawill, M.M. David, J. Biol. Chem., 177, (1949), 751– 766. 22 M. Taniguchi, H. Hirayama, T. Sakagami, Biochim. Biophys. Acta, 296, (1973), 65– 70. 23 J.G. Parkes, W. Thompson, J. Biol. Chem., 248, (1973), 6655– 6662. 24 K.W.A. Wirtz, Golde L.M.G. van, Deenen L.L.M. van, Biochim. Biophys. Acta, 218, (1970), 176– 179. Citing Literature Volume74, Issue2Fifth FEBS‐Ferdinand Springer LectureMarch 01, 1977Pages 220-224 ReferencesRelatedInformation

Details of a systematic approach to suitability testing of commercial control sera are given for substrate optimized L-aspartate aminotransferase and L-alanine aminotransferase methods at 37 degrees C. Their acceptability for control purposes of standardized methods depends on: (1) the range of control values in relation to borderline values, (2) stability, (3) aspect, clarity, (4) NADH consumption in preincubation time, (5) blank activities, (6) kinetic data as half saturation constants and saturation curves, (7) influence of effectors, (8) isoenzyme pattern. These evaluation criteria are proposed for suitability testing. The term "representativeness" should be introduced as a special criterion for main characteristics of control materials. The authors want to point out the close connection with standardization of methods.

We investigated the enzyme activity of the blank in the spectrophotometric determination of the aminotransferase activities and aspartate aminotransferase activity. 6 lactate dehydrogenase and 3 malate dehydrogenase preparations from different manufactures and from different organs showed additional and contaminating activity. The additional activity depends upon the 2-oxoglutarate concentration. The contaminating activity is caused by alanine aminotransferase and aspartate aminotransferase in the auxiliary enzymes. We propose that exact definitions must be given for the auxiliary enzymes in the recommendations of standard determinations for enzyme activities.

Abstract. The fatty acid distribution of the main lipid fractions: triglycerides (TG), phosphatidylcholine (PCh), phosphatidylethanolamine (PE), and sphingomyelin (Sph) of muscle from 6 patients with progressive muscular dystrophy (p.m.d.), Duchenne, 8 to 12 years old was estimated and compared with normal controls of different age. In view of the results of several authors about varied fatty acid distribution in immature muscle a third group comprising samples of neonatal muscle was studied. 1. The fatty acid pattern of the lipid fractions TG, Sph, and PE from muscle of patients with p.m.d. shows no important variation in comparison to normal controls. In contrast to this the fatty acid distribution in PCh is extremely varied: the percentage of 18:2 is decreased and correspondingly the content of 18:1 is increased. In view of the high percentage (nearly 10 %) in which linoleic acid is substituted by oleic acid in PCh, effects on the plasma membrane are to be expected. 2. The fatty acid pattern in neonatal muscle shows in nearly all positions of the fractions TG, Sph, PE, and PCh a different distribution from normal or dystrophic muscle. In view of the most important variation in dystrophic muscle it must be stated that generally 18:2 is decreased. This deficit was replaced by an increase of all other fatty acids (not only at a substitution by 18:1 as given in p.m.d.). Therefore the diminished content of linoleic acid in PCh of neonatal and dystrophic muscle cannot be interpreted as expression of a corresponding or similar lipid metabolism in both tissues. The results were seen as signs of significant qualitative alterations especially of PCh in p.m.d. They were discussed as proof of our thesis that the basic defect in p.m.d. concerns the specific acylation of PCh with linoleic acid.

The relationship between temperature and the behaviour of aspartate aminotransferase was investigated in the presence of pyridoxal 5'-phosphate. The addition in vitro of pyridoxal 5'-phosphate caused an increase in the activity and altered the thermal behaviour of aspartate aminotransferase. In choosing the temperature for the determination of enzymic activity, the concentration of the coenzyme must therefore also be considered.