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Questions related from Luis Peña
I would like to use a crystal structure of the heme group from PDB for my thesis, for the introductory topic of cofactors (Figure 2, 10.1111/j.1432-1033.2004.04411.x ). The published figure has...
20 August 2020 2,007 3 View
I am searching for a solution containing both essential and non-essential amino acids. Mammalian cell culture seems to use these quite often, I would like to know if someone has experience using...
17 March 2020 7,939 3 View
I made the vitamin solution acc. to Wolfe as follows: I made stock solutions of these compounds at 10 mg per mL, then for each compound the corresponding volume was diluted in 50 mL, and the...
02 March 2020 907 0 View
I have to use hydrogen peroxide to verify the redox state of an organic cofactor by LC-MS measurement. However I have realized that commercial H2O2 contains stabilizers to reduce decomposition to...
19 November 2019 1,331 3 View
The protocol of Thermo Scientific NiNTA resin (cat. 88221) for purification of proteins containing a hexahistidine tag use an elution buffer containing 250 mM imidazole. For fun after this elution...
02 August 2019 4,417 3 View
For vacuum lyophilization of proteins, are volatile MS buffers like ammonium bicarbonate suitable, or their "volatile" properties only applies in ESI spray, while in lyophilization the salt...
23 July 2019 7,477 0 View
My experiment involve a dehydrogenase and I would like to identify the optimal substrate. For this an assay was established based on the use of DCPIP as cofactor, which when reduced the absorbance...
12 January 2019 2,660 5 View
Hello and good day. I am using a Q Exactive Plus and in the experiment pane for a Full MS / ddMS2 (TopN) there are three settings for the automatic gain control (AGC), the number of ions to be in...
06 January 2019 439 5 View
I am working on metabolomics of Streptomyces (wild type and over-expressing strains, so I have to use contrasting strains) and I am considering methods for normalization of the inoculum, for...
20 November 2018 8,923 5 View
Simple reagents like sugar solutions or BSA stocks, do you wait until the vial content has melted completely, or you use it once the volume you need is available and then back in the freezer?
22 February 2018 8,922 3 View
I have a maltose binding fusion protein being purified with the MBPTrap column (GE). I get very little protein (less than 1 mg from a 400 mL E. coli BL21 (DE3) culture) during the elution step...
27 November 2017 7,044 7 View
What are the advantages and disadvantages of using a volatile or a non-volatile buffer for anion exchange chromatography in an FPLC? Is it only related to further processing , like freeze drying...
07 November 2017 7,121 3 View
The default settings of the FPLC UV detector are for wavelengths 215, 255, 280 and 495 nm. I know that the 280 nm is the most important since it directly measures protein via the aromatic ring in...
17 August 2017 558 2 View
I'm trying to set up a vital stain protocol with fluorescein diacetate and propidium iodide to verify if a sample of sponge and bacteria cells is still alive after an incubation of 4 months, but I...
10 October 2014 3,451 5 View
I'd like to know which is better for protein extraction from E. coli: glass beads or silica zirconium beads. In my lab silica zirconium beads are used for DNA extraction from M. tuberculosis, and...
15 July 2013 5,768 2 View
I have a few sequences described as enzymes with lypolityc activity and I'm extracting the domains characteristics of said activity using Pfam and MEME (I'm following a procedure described by...
14 May 2013 6,455 4 View
I am writing my thesis about metabolomics, and after reading about metabolites and proteins and how these have been measured through time for characterization and kinetics, I think metabolomics...
01 January 1970 2,161 2 View
