WO2001094924A2 - Verfahren zur analyse enzym-katalysierter umsetzungen mit maldi-tof-massenspektrometrie - Google Patents
Verfahren zur analyse enzym-katalysierter umsetzungen mit maldi-tof-massenspektrometrie Download PDFInfo
- Publication number
- WO2001094924A2 WO2001094924A2 PCT/EP2001/006416 EP0106416W WO0194924A2 WO 2001094924 A2 WO2001094924 A2 WO 2001094924A2 EP 0106416 W EP0106416 W EP 0106416W WO 0194924 A2 WO0194924 A2 WO 0194924A2
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- WIPO (PCT)
- Prior art keywords
- enzyme
- product
- maldi
- starting material
- analysis
- Prior art date
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/04—Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components
Definitions
- the present invention relates to a method for analyzing enzyme-catalyzed reactions of non-polymeric starting materials to non-polymeric products using MALDI-TOF mass spectrometry, preferably in the presence of an internal standard on a special carrier material.
- a major problem in the screening for new enzymatic activities is the quick and easy identification of the products formed in the enzymatic reaction and / or, where appropriate, the decrease in the starting material used.
- Methods such as NMR, which can be used after working up, for example by salt precipitation and / or subsequent chromatography, can also be used for the analysis.
- HTS high-throughput screening
- MALDI-TOF-MS matrix-assisted laser desorption ionization with time-of-flight mass spectrometry
- MALDI-TOF-MS matrix-assisted laser desorption ionization with time-of-flight mass spectrometry
- the quality of a MALDI spectrum depends to a large extent on the morphology of the sample examined (Garden & Sweedler, Anal. Chem. 72, 2000: 30-36 ).
- Significant differences in the occurrence of signals, the intensity, the resolution and the mass accuracy can be observed as soon as a MALDI sample is examined at different locations (Cohen & Chait, Anal. Che., 68, 1996: 31-37 ; Strupat et al., Int. J. Mass Spectrom. Ion Processes, 111, 1991: 89-102; Amado et al., Rapid Commun.
- the samples are usually applied in a thin layer to a metal surface and then irradiated with a pulsed laser.
- a pulsed laser By focusing the emitted ions, the resolution of the mass spectra in the lower mass range can be increased to about 5000 D.
- the MALDI-TOF-MS is an interesting simple and quick method that provides specific information about the analyzed substances, so that the use of the MALDI-TOF-MS for measuring enzymatic reactions with low molecular substances would be desirable. In particular, their use in high-throughput screening would be desirable.
- the task therefore was to develop a method for analyzing enzyme-catalyzed reactions using MALDI-TOF mass spectrometry.
- This object was achieved by a process for the analysis of enzyme-catalyzed reactions of non-polymeric starting materials to non-polymeric products, characterized in that the starting material and product of the enzyme-catalyzed reaction are analyzed using MALDI-TOF mass spectrometry, the process comprising the following steps :
- Enzyme-catalyzed reactions are understood to mean enzymatic reactions with whole cells, which can be of plant, animal, bacterial or fungal origin, and yeast cells are also suitable. The enzymatic conversion can take place with resting, growing, permeabilized or immobilized cells or microorganisms. Enzymes are also suitable for the enzyme-catalyzed implementation. These enzymes can still be contained in the permeabilized cells or microorganisms or they can also be present in so-called crude extracts. For a faster and generally also by-product-free reaction, aria-purified or purified enzymes are used, which can be used in the reaction as free or immobilized enzymes. The reaction is preferably carried out with free, purified, purified or immobilized enzymes.
- Enzymes of enzyme classes 1 to 6 are advantageously used in the process according to the invention, preference is given to enzyme classes 1 to 4, particularly preferably enzyme class 3 such as classes 3.1 (reaction with ester bonds), 3.2 (glycosidases ), 3.3 (reaction with ether bonds), 3.7 (reaction with carbon-carbon bonds), 3.11 (reaction with carbon-phosphorus bonds), enzymes such as lipases, esterases or phosphatases such as phytases are very particularly preferred. More beneficial Enzymes can be found in enzyme class 6.
- reaction solutions of the process according to the invention it is not necessary to clean the reaction solutions of the process according to the invention before analysis with MALDI-TOF mass spectrometry.
- the reaction can be measured directly. This also applies to complex sample mixtures. Also, no pure substances have to be used for the reaction, although this is of course possible.
- Educts and / or products which are poorly or not at all detectable in MALDI-TOF-MS can advantageously be derivatized before the analysis (see examples) and thus finally analyzed.
- the derivatization can take place before or after the enzymatic reaction.
- Derivatization is particularly advantageous in cases in which hydrophilic groups are introduced into hydrophobic or volatile compounds, such as esters, amides, lactones, aldehydes, ketones, alcohols, etc., which advantageously also carry an ionizable functionality.
- Examples of such derivatizations are reactions of aldehydes or ketones to oximes, hydrazone or their derivatives or alcohols to esters, for example with symmetrical or mixed anhydrides.
- An internal standard is advantageously added in the method according to the invention for analyzing enzyme-catalyzed reactions.
- This internal standard advantageously enables the quantification of the low molecular weight compounds in the reaction solution.
- This standard can be added to the enzyme-catalyzed reaction before, during or after the end of the enzymatic reaction.
- the starting material and product or, if appropriate, further intermediate products of the reaction can thus be analyzed and ultimately quantified.
- the intermediate products are ultimately also to be understood as products of the starting material used at the start of the reaction.
- the method according to the invention can also be used to monitor or analyze enzyme reactions which catalyze the successive reaction. These can be catalyzed by one or more enzymes. By-products can also be analyzed.
- Labeled substances are advantageously used as the internal standard, but in principle chemical compounds similar to the starting materials and / or products are also suitable as the internal standard. Similar chemical compounds of this type are, for example, so-called compounds of a homologous series, the members of which differ only by, for example, an additional methylene group.
- an internal standard at least one isotope is preferably selected from the group 2 H,
- the starting material is advantageously selected from at least one isotope from the 2 H, i3 C, i5 N, 17 0, i8 0, 33 S, 34 s, 36 S, 35 C1, 37 C1, 29 Si, 30 Si, 74 Se or their mixtures marked.
- 2 H or i3 C is preferably used as the isotope.
- a distance of the marking from greater than or equal to 3 daltons to less than or equal to 10 daltons is advantageously sufficient.
- a measurement is also under 3 Dalton or above 10 daltons in principle possible, but which may isotope effects may occur at small distances may be interference with the isotopes of the analyte or at greater distances'. This making the measurements difficult does not make them impossible.
- a marked internal standard it is also advantageous to choose a substance that has the highest possible homology, that is to say structural similarity, to the chemical compound to be measured. The higher the structural similarity, the better the measurement results and the more accurately the connection can be quantified.
- a ratio of analyte to internal standard is advantageously set in a range from 0.1 to 15, preferably in a range from 0.5 to 10, particularly preferably in a range from 1 to 5.
- the analysis samples are advantageously concentrated in the smallest possible space or on the smallest possible diameter in order to achieve a further improvement in the measurement point resolution or measurement accuracy.
- the reaction samples in the method according to the invention can be prepared manually or advantageously automatically using conventional laboratory robots.
- the analysis with MALDI-TOF-MS can also be carried out manually or advantageously automatically.
- MALDI mass spectrometry can advantageously be used for the rapid screening of enzyme-catalyzed reactions in so-called high-throughput screening.
- the MALDI-TOF-MS is characterized by a high sensitivity with the lowest sample consumption.
- new enzyme activities and new mutants of known enzymes can be rapidly identified after a mutagenesis, for example via a classic mutagenesis with chemical agents such as NTG, radiation such as UV radiation or X-rays or after a so-called site-directed mutagenesis, PCR mutagenesis or the so-called gene shuffling can be found.
- Carrier materials with a roughness value or a roughness number of R z greater than 1, preferably greater than 2, particularly preferably greater than 3, very particularly preferably greater than 4 are advantageously used for the process according to the invention.
- R z means the average roughness depth ( ⁇ m) as the arithmetic mean of the individual roughness depths of five adjacent individual measuring sections. The Roughness depth is determined according to DIN 4768.
- These carrier materials are polished, coated or vapor-coated carrier materials or polished and coated or polished and vapor-coated carrier materials.
- the carriers consist of a material selected from the group of glass, ceramic, quartz, metal, stone, plastic, rubber, silicon, germanium or porcelain. The material preferably consists of metal or glass.
- the analysis can additionally be carried out with the aid of the metastable method
- the dynamics of the marking pattern and the concentration of starting material and product are advantageously measured in the method according to the invention. This enables enzyme kinetics to be analyzed. In this way, K m and V max of an enzyme can be determined.
- Matrix / analyte ratio 50 (mg / mg)
- PEA was determined quantitatively in all experiments. It could be shown that MET can be determined quantitatively if PEA is used as the internal standard, but the errors were significantly greater due to the different molecular structure of the two compounds and the associated different flight and flight characteristics. A similar behavior was observed when PEA against phenylmethylamine was determined as the internal standard ( Figure la). The best results were obtained when the internal standard has the highest possible molecular homology, that is to say structural similarity, to the analyte, such as, for example, ds-PEA to PEA (FIG. 1b).
- the ratio of analyte to standard was varied from 0.1 to 10 times.
- the result can be seen in FIG. 2.
- the sample application was carried out using a nano-plotter, the measurement by manually approaching the spots in the MALDI. 13 positions of 25 shots each were measured per spot, which were then added up. All concentrations were determined 4 times.
- the absolute concentration of the internal standard was 0.14 mg / ml.
- Samples are prepared according to the pipetting scheme given above (example 1) and transferred to a 6-well plate.
- the nano-plotter is programmed so that 50 ⁇ l of the sample solution is drawn up per concentration; For each concentration, four spots are spotted on different fields of the MALDI target (quadruple determination).
- FIG. 2 shows the quantitative determination of PEA against ds ⁇ PEA as an internal standard. You can clearly see a saturation of the curve if the ratio between analyte and internal standard is too high.
- Detector limit are (256 counts / shot), while the signal of the internal standard is just above the required quality criterion of the signal / noise ratio.
- the concentration of the internal standard or the ratio of analyte for example the product to the internal standard, can easily be calculated in order to be in a favorable ratio to the analyte.
- the relative standard deviation was usually less than 5% in this experiment in '.
- Example 3 Sample application with a nano plotter
- Sample preparation using a nano plotter is intended to apply the smallest possible amount of the matrix / analyte mixture and to cause the solvent to evaporate as quickly as possible, thereby reducing the segregation of both components. It could be shown that the nano-plotter allows a simple and quick preparation of MALDI samples, with which reproducible results can be obtained in the quantification.
- the matrix crystals are significantly smaller compared to manual preparation.
- the distribution of the analyte in the matrix appears to be somewhat more homogeneous than with a manual preparation (data not shown).
- "fried egg-like" structures formed with this type of preparation that is, the matrix and analyte form a ring, in the middle of which no (or at least significantly less) ionizable
- the parameters of this software could be optimized for the measurement of small molecules.
- the following points were taken into account in the automatic data acquisition: Saturation effects of the signals of the matrix; analyte or internal standard; Saturation of the detector limit; Laser intensity; Resolution of the peaks; Signal / noise ratio; Baseline noise and summation of the appropriate signals.
- FIG. 4 shows an example of a calibration line that was recorded using these parameters.
- the samples were identical to those measured in Example 2b ( Figure 3).
- the sample preparation was carried out by means of a nano plotter, the recording spiral was not optimized for these small sample drops, so that a large number of laser shots did not hit the samples (four spots were measured for each concentration). Nevertheless, an analogous result to the classic recording technique shown in FIG. 3 was obtained. With this classic recording technique, the measurement spots were approached or sighted manually and fired at 13 different positions with 25 laser shots each. The signals from these 13x25 measurements were added up by the MALDI and represent the result of a single measurement. Analogous results were also obtained with manual sample preparation. The use of the AutoXecute TM program thus enables automated quantification of small molecules.
- Hydrophobically coated plate with small holes (the holes themselves have the same properties as the unpolished target).
- Figure 5a shows the manual application
- Figure 5b shows the automatic application.
- FIGS. 7 a) to c) shows the quantitative analysis of PEA (7 ⁇ g / ml to 1400 ⁇ g / ml) against ds-PEA (140 ⁇ g / ml) as an internal standard on various targets.
- the samples were applied manually (0.34 ⁇ l per well).
- the average standard deviation for all three targets was approximately 10%.
- Example 5 Lipase-catalyzed preparation of enantiomerically pure IS, 2S-methoxycyclohexanol (MC)
- Table 1 lists the molar masses and the expected ions (calculated) of the individual compounds.
- Table 2 lists the different matrices with which the measurements were carried out and the results of these measurements.
- Table 2 Matrices used and results of the measurements in positive and negative mode. +: Signal detected, -: signal not found, * overlap of a (theoretical) signal with a signal of the matrix.
- SDS sodium dodecyl sulfate
- analyte methoxycyclohexanol (BASF)
- b derivatization reagent: 2-sulfobenzoic acid cyclic
- MC Methoxycyclohexanol
- Table 3 Matrices for the measurement of the derivatized methoxycyclohexanol (MCS).
- the samples were spotted onto the MALDI target by means of a nano plotter, the conditions of the DHB / PEA solutions previously used being used (see Pipettiersche a and nano plotter description, Example 1). Satellite peaks were observed in some cases, but they did not affect the measurement in any way. The peaks were homogeneous (optical impression from the MALDI microscope and binocular).
- FIG. 9 shows the results of the quantitative MALDI of MCS against d-MCS as an internal standard.
- FIG. 10 shows the percentage conversion of the enantiomerically pure methoxycyclohexanol measured at different matrix / analyte ratios. The deviation with a low M / A ratio is probably due to the poor signal-to-noise ratio in this series of measurements.
- the signal recording should advantageously take place with a signal / noise ratio greater than 3; as a quality feature, this ratio should advantageously be greater than 10, which is easily achieved under the conditions examined.
- the laser strength (attenuation) should advantageously be chosen as weak as possible (“ajbove threshhold”) in order to avoid oversteering at the detector and excessive fragmentation of the analyte.
- Scout 384-well target optionally: - polished Bruker standard metal target or - Bruker glass target (prototype) or
- GeSim micropipetting system nano-plotter type: P30-X-D - Deutschen für Silicon-Mikrosysteme mbH, conerkmanns- dorf / Rossendorf Piezoelectric micropipette from the same company
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- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
- Measuring Or Testing Involving Enzymes Or Micro-Organisms (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/296,381 US7445885B2 (en) | 2000-06-07 | 2001-06-06 | Method for analyzing enzyme-catalyzed reactions using MALDI-TOF mass spectrometry |
CA002411727A CA2411727A1 (en) | 2000-06-07 | 2001-06-06 | Method for analysing enzyme-catalysed reactions using maldi-tof mass spectrometry |
JP2002502424A JP2003536070A (ja) | 2000-06-07 | 2001-06-06 | Maldi−tofマススペクトロメトリーによる酵素が触媒する転化の分析 |
EP01960274A EP1287343A2 (de) | 2000-06-07 | 2001-06-06 | Verfahren zur analyse enzym-katalysierter umsetzungen mit maldi-tof-massenspektrometrie |
AU2001281809A AU2001281809A1 (en) | 2000-06-07 | 2001-06-06 | Method for analysing enzyme-catalysed reactions using maldi-tof mass spectrometry |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10027794A DE10027794A1 (de) | 2000-06-07 | 2000-06-07 | Verfahren zur Analyse Enzym-katalysierter Umsetzungen mit MALDI-TOF-Massenspektrometrie |
DE10027794.2 | 2000-06-07 |
Publications (2)
Publication Number | Publication Date |
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WO2001094924A2 true WO2001094924A2 (de) | 2001-12-13 |
WO2001094924A3 WO2001094924A3 (de) | 2003-01-09 |
Family
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Application Number | Title | Priority Date | Filing Date |
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PCT/EP2001/006416 WO2001094924A2 (de) | 2000-06-07 | 2001-06-06 | Verfahren zur analyse enzym-katalysierter umsetzungen mit maldi-tof-massenspektrometrie |
Country Status (7)
Country | Link |
---|---|
US (1) | US7445885B2 (de) |
EP (1) | EP1287343A2 (de) |
JP (1) | JP2003536070A (de) |
AU (1) | AU2001281809A1 (de) |
CA (1) | CA2411727A1 (de) |
DE (1) | DE10027794A1 (de) |
WO (1) | WO2001094924A2 (de) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004029286A2 (de) * | 2002-09-19 | 2004-04-08 | Charité - Universitätsmedizin Berlin | Verfahren zur erkennung von enzymaktivitäten |
US6930305B2 (en) * | 2002-03-28 | 2005-08-16 | Mds, Inc. | Method and system for high-throughput quantitation of small molecules using laser desorption and multiple-reaction-monitoring |
JP2006520465A (ja) * | 2003-02-20 | 2006-09-07 | ルミゲン インク | 過酸化水素検出方法に用いるシグナリング化合物 |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6870154B1 (en) | 2004-02-27 | 2005-03-22 | The University Of Western Ontario | Capillary mixer with adjustable reaction chamber volume for mass spectrometry |
DE102004019043B4 (de) * | 2004-04-16 | 2008-08-21 | Justus-Liebig-Universität Giessen | Präparationsverfahren für die Mikrobereichsanalytik der Zusammensetzung von Substanzgemischen |
JP6233929B2 (ja) * | 2014-03-18 | 2017-11-22 | 学校法人上智学院 | 化合物、これを用いた定量分析用標準物質およびデスモシン類の定量方法 |
WO2017027468A1 (en) * | 2015-08-07 | 2017-02-16 | Northwestern University | Cellular assays with a molecular endpoint measured by samdi mass spectrometry |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3948731A (en) * | 1974-10-24 | 1976-04-06 | Massachusetts Institute Of Technology | Method and apparatus for measuring reactant concentrations and quantities |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995009688A1 (en) * | 1993-10-04 | 1995-04-13 | Hewlett-Packard Company | Sample preparation system and method |
US5777324A (en) * | 1996-09-19 | 1998-07-07 | Sequenom, Inc. | Method and apparatus for maldi analysis |
US6268131B1 (en) * | 1997-12-15 | 2001-07-31 | Sequenom, Inc. | Mass spectrometric methods for sequencing nucleic acids |
EP1329513B1 (de) * | 1998-08-25 | 2011-12-07 | University of Washington | Schnelle quantitative Analyse von Proteinen oder Proteinfunktionen in komplexen Gemischen |
DE19913858A1 (de) * | 1999-03-26 | 2000-09-28 | Studiengesellschaft Kohle Mbh | High-Throughput-Screening-Verfahren zur Bestimmung der Enantioselektivität asymmetrisch verlaufender Reaktionen |
ATE504937T1 (de) * | 1999-04-27 | 2011-04-15 | Bio Rad Laboratories | Probenhalter für ein gasphaseionenspektrometer |
-
2000
- 2000-06-07 DE DE10027794A patent/DE10027794A1/de not_active Withdrawn
-
2001
- 2001-06-06 JP JP2002502424A patent/JP2003536070A/ja active Pending
- 2001-06-06 CA CA002411727A patent/CA2411727A1/en not_active Abandoned
- 2001-06-06 US US10/296,381 patent/US7445885B2/en not_active Expired - Fee Related
- 2001-06-06 EP EP01960274A patent/EP1287343A2/de not_active Ceased
- 2001-06-06 WO PCT/EP2001/006416 patent/WO2001094924A2/de active Application Filing
- 2001-06-06 AU AU2001281809A patent/AU2001281809A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3948731A (en) * | 1974-10-24 | 1976-04-06 | Massachusetts Institute Of Technology | Method and apparatus for measuring reactant concentrations and quantities |
Non-Patent Citations (2)
Title |
---|
MOO J S ET AL: "Application of capillary electrophoresis to determination of enzyme activity and other properties of phosphatidylinositol-specific phospholipase C" JOURNAL OF CHROMATOGRAPHY A, ELSEVIER SCIENCE, NL, Bd. 781, Nr. 1-2, 26. September 1997 (1997-09-26), Seiten 263-270, XP004094556 ISSN: 0021-9673 * |
See also references of EP1287343A2 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6930305B2 (en) * | 2002-03-28 | 2005-08-16 | Mds, Inc. | Method and system for high-throughput quantitation of small molecules using laser desorption and multiple-reaction-monitoring |
WO2004029286A2 (de) * | 2002-09-19 | 2004-04-08 | Charité - Universitätsmedizin Berlin | Verfahren zur erkennung von enzymaktivitäten |
WO2004029286A3 (de) * | 2002-09-19 | 2004-07-08 | Charite Universitaetsmedizin | Verfahren zur erkennung von enzymaktivitäten |
JP2006520465A (ja) * | 2003-02-20 | 2006-09-07 | ルミゲン インク | 過酸化水素検出方法に用いるシグナリング化合物 |
Also Published As
Publication number | Publication date |
---|---|
WO2001094924A3 (de) | 2003-01-09 |
DE10027794A1 (de) | 2001-12-13 |
CA2411727A1 (en) | 2001-12-13 |
EP1287343A2 (de) | 2003-03-05 |
AU2001281809A1 (en) | 2001-12-17 |
JP2003536070A (ja) | 2003-12-02 |
US7445885B2 (en) | 2008-11-04 |
US20030164449A1 (en) | 2003-09-04 |
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