MOPS, MES, and MOPSO, what is the difference between them

The zwitterionic buffer, also known as Good's Buffer, is a series of N-substituted sulfamic acids that have good pH stability and are inert to a variety of chemicals and enzymes. Among them, the morpholinic buffers, including MOPS Sodium Salt, MES, and MOPSO, have some common character, for example, they do not form complexes with most metal ions and are therefore suitable for solutions containing metal ions. But what is the difference between them?

Let’see the following table:

Table 1. The comparation of MOPS, MES, MOPSO.

Buffer	Structure	Full Name	Formula	pKa(25°C)	Buffering range
MOPS		3-(N-morphine) Propanesulfonic acid	C7H15NO4S	7.14	6.5~7.9
MES		2-(N-morpholino) ethanesulfonic acid	C6H13NO4S	6.1	5.5~6.7
MOPSO		3-(N-morpholino)-2-hydroxypropanesulfonic acid	C7H15NO5S	6.87	6.2~7.6

The application of MOPS, MES and MOPSO:

MOPS:

(1) running buffer in electrophoresis and protein purification in chromatography;

(2) Formulated into a variety of agar medium for the culture of bacteria, yeast and mammalian cells;

(3) Lysis buffer that can be used for Escherichia coli cells;

(4) as eluent in gel filtration chromatography;

(5) Northern blot as a buffer for RNA isolation and transfection;

(6) For bicinchoninic acid (BCA) assay;

(7) Studies on electron transport and phosphorylation of chloroplast sample preparation

MES:

(1) Biological buffer, can be used to replace highly toxic cacodylate, and ion buffer citrate and malate;

(2) Buffered media commonly used for bacterial, yeast and mammalian cells. High concentrations of MES are toxic to most plants, but can be used in plant media at concentrations ~10 mM;

(3) as a buffer for studying Tau protein in culture;

(4) Because of its low ion mobility and low conductivity at high concentrations, it can be used in many types of electrophoresis and chromatography including capillary electrochromatography, gel filtration chromatography, phosphocellulose column chromatography, hydrophobic interaction chromatography, cation exchange chromatography and SDS-PAGE;

(5) Complex with organotin (IV) molecules as antitumor agents.

MOPSO:

(1) use as a carrier electrolyte in capillary electrophoresis, and as a crystallization buffer for glutathione synthetase;

(2) used in fluorescence spectrometry, spectrophotometry and isothermal titration calorimetry;

(3) Interaction with the peptide backbone of bovine serum albumin (BSA) to prevent thermal denaturation of BSA;

(4) as one of the buffer components for copper correlation analysis;

(5) used as a buffer carbon yeast extract medium composition;

(6) MOPSO-ethanol buffer system was prepared to fix urine-derived cells;

(7) A buffer system for the determination of biological by-products of marine crude oil.

Although Good's buffer has the advantages of not participating in and not interfering with the biochemical reaction process, not inhibiting the enzymatic chemical reaction, and not reacting with the metal ion. However, in the specific use, there are still some differences in the application range of several morpholine series buffers MES, MOPS （CAS 1132-61-2） and MOPSO. Therefore, it is necessary to consider the buffer requirements and specific experimental types so as to select the most appropriate buffer.

Edited by Suzhou Yacoo Science Co., Ltd.

The incompleted transfer of protein in WB? CAPS may help you!

We always encountered various problems in Western Blot (WB):

•  Incomplete transfer of protein?
•  High background?
•  No positive bands?

......

Below we will give corresponding solutions to the possible reasons for the problem of insufficient transfer of protein, and hope it can help you succeed in the experiment.

1. Why does the transfer of protein is needed?

Western Blot is a method in which proteins are transferred to a membrane and then detected using an antibody. For known expression proteins, the corresponding antibody can be used as a primary antibody for detection, and the expression product of the new gene can be detected by the fusion portion of the antibody.

The protein sample separated by PAGE is transferred to a solid phase carrier (for example, a nitrocellulose membrane), and the solid phase carrier adsorbs the protein with a non-covalent bond, and can maintain the type of polypeptide and its biological activity. The protein or polypeptide on the solid phase carrier is used as an antigen, and the corresponding antibody is immunoreactive, and then reacted with the enzyme or the isotope-labeled secondary antibody, and the protein expressed by specific gene is detected by substrate color development or autoradiography.

2. The reason and solution of the incompleted transferance

Reasons	Solutions
The film is not completely soaked	Use 100% methanol permeable membrane
molecular weight of Target protein is less than 10,000	Select a small pore size membrane to shorten the transfer time
The isoelectric point of the target protein is equal to or close to the pH of the transfer buffer	Try using other buffers such as N-Cyclohexyl-3-Aminopropanesulfonic Acid (CAPS) buffer (pH 10.5) or using low pH buffers such as acetate buffer
Methanol concentration is too high	Excessive methanol concentration causes the protein to separate from the SDS, thereby precipitating in the gel, while causing the gel to shrink or harden, thereby inhibiting the transfer of high molecular weight proteins. Reduce methanol concentration or use ethanol or isopropanol instead
Insufficient transfer time	Extended transfer time for thick gels and high molecular weight proteins

3. Preparation method for CAPS (CAS 1135-40-6) buffer

Please see the following table (Both concentrations of buffer and sodium hydroxide are 0.1 mol/L):

pH of CAPS Buffer	Volume （CAPS）	Volume (NaOH)
6.8	250	0
10.0	218.3	31.7
10.5	178.6	71.4
10.8	156.3	93.7
11.2	138.9	111.1

The specific operation of the preparation is: 0.1 mol/L CAPS buffer solution is first prepared in a volumetric flask. During the configuration process, the buffer has to be dehydrated at a high temperature and cooled in a desiccator; 0.1 mol/L sodium hydroxide solution is also formulated at the same time. According to the formula in the above table, a buffer solution corresponding to pH can be prepared, and sodium hydroxide is mainly used to adjust the pH.

Western blotting can be applied to detect target proteins from protein mixtures, quantitatively or qualitatively determine the expression of proteins in cells or tissues, and subsequent analysis of protein-protein, protein-DNA, and protein-RNA interactions. Film transfer is the basis of WB, and its quality is the key to the success of WB. We hope that the above methods can help you succeed in the process of transfor.

Edited by Suzhou Yacoo Science Co., Ltd.

How to check if our somabiotech Somatropin is original

Recently, we've been reported by our customers that counterfreit Somabiotech brand of HGH 10iu appeared on the market. We now inform you that all our Somabiotech somatropin is with anti-counterfeit labels, if there is no anti-counterfeit label in the packaging, all are considered to be counterfeit products.

You can also verify the Security code in our website. Here it is the link for it:
http://v.cnbyi.com/kh/Somabiotech/ac.htm

How to choose a polypropylene model suitable for your enterprise sewage treatment？

How to choose a polypropylene model ？

Although polyacrylamide is favored by everyone in sewage treatment, it is not a panacea, not a single model can solve all the problems, and different types and models of polyacrylamide are needed for different water quality of sewage.


Different enterprises of the nature of the wastewater is different, have plenty of acidic water, have plenty of alkaline water quality, and water quality is neutral, some containing oil, some contain lots of organic compounds, some color, some contain large amounts of sediment, there are all kinds of situation, foshan jianmei aluminum group is a large aluminum plant, the company to provide customers the anionic polyacrylamide have solved the problem of aluminum sewage, and get the customers satisfied with the products. So, how to choose the right polyacrylamide better and more reasonably?


Generally speaking, the treatment effect of cationic polyacrylamide is good for wastewater with acidic water quality, and anionic polyacrylamide is good for wastewater with alkaline water quality. Of course, the quality of neutral sewage shows relatively alkaline and acidic sewage is easy to treat. If the water quality of sewage is too acidic, it is generally difficult to treat. The usual practice is to add alkali into the sewage to adjust the ph of sewage so that the sewage reaches the best neutral level.
On the contrary, if the sewage shows high alkaline strength, it is necessary to add acid to adjust the ph of the sewage. Through repeated experimental comparison, select the model with the best experimental effect, and then check whether the selected model is also suitable for production in the actual production process.

Preparation of porous zinc oxide microspheres guided by HEPES

HEPES is abbreviated of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, which is a Good's buffer with pH buffer range of 6.8~8.2, and widely used in cell culture because of its good ability at maintaining physiological pH. It can also be used to prepare porous zinc oxide microspheres.

As a II-VI semiconductor compound, zinc oxide has a band gap of 3.37 eV and an exciton binding energy of 60 meV. Due to its special piezoelectric and optical properties, zinc oxide is widely used in many fields such as solar cells, sensors, and voltage sensitive resistors, piezoelectric materials, antibacterial agents, and photocatalysis fields. The morphology and size of zinc oxide have an important influence on its properties and applications, especially porous zinc oxide microspheres, which exhibit low density and high specific surface properties in catalysts, gas sensors, drug delivery and other fields.

At present, different methods have been reported to synthesize porous zinc oxide microspheres, such as high temperature calcination, chemical vapor deposition, and chemical bath deposition. However, these methods have high reaction temperatures, are complicated to operate, and are difficult to control. The solvothermal method is widely used for the synthesis of zinc oxide micro/nano materials due to its simple equipment and mild reaction conditions. However, the synthesis of porous zinc oxide microspheres by solvothermal method often requires the addition of a templating agent or a porogen. After the completion of the reaction, further post-treatment is required to remove the templating agent, which increases the complexity of the process and environmental pollution.

In order to solve the above problems, the researchers [1] developed a preparation method for porous zinc oxide microspheres by using HEPES molecules, which has low cost and simple operation, and the obtained zinc oxide has uniform morphology, high specific surface area and multi-stage pore structure. The specific operations are as follows:

(1) 2~6 mmol of organic zinc salt (zinc acetate or zinc acetylacetonate) are sonicated in 30~70mL organic solvent (TEG, DEG, EG, DMF) for 10 minutes, then add 2~8 mmol HEPES;

(2) The mixed solution is placed in a stainless steel high pressure autoclave lined with 100 mL of polytetrafluoroethylene, and reacted at 150°C for 6 to 18 hours;

(3) The obtained product was washed by centrifugation at 10000 rpm/min for 10 minutes, and the supernatant was removed, repeat 5 times to remove the residual solvent and HEPES. The product was dried in a 60°C oven for 24 hours and then naturally cooled.

In this method, HEPES molecules play an important role in the formation of porous zinc oxide microspheres. After the addition of the HEPES molecule, it is adsorbed on the surface of the nucleus by electrostatic interaction with the zinc oxide seed crystal in the sol. The presence of the HEPES molecule blocks further clustering and aggregation of the nucleus. Porous zinc oxide microspheres are formed by the continued growth of the HEPES molecules under solvothermal conditions. The HEPES molecules and solvent in the surface and voids of the microspheres can be completely removed after multiple washings with deionized water.

HEPES (CAS 7365-45-9) molecules have the advantages of non-toxicity and environmental friendliness. The method is easy to operate, simple in equipment, low in synthesis temperature, low price in raw materials, good in repeatability, and suitable for industrial production. The prepared porous zinc oxide microsphere has the advantages of uniform size, multi-stage pore structure (pore size 4~30 nm) and large specific surface area (43.4~69.6m2/g), and can be used as photocatalyst and gas sensor.

Reference

[1]CHEN Rong, LI Qin, YANG Hao, Lv Zhong. A preparation method of porous zinc oxide microspheres guided by HEPES molecularly. 2014, CN103482682A.

Edited by Suzhou Yacoo Science Co., Ltd.

Modification of zein functional drug-loaded microsphere with TRIS

As a common biological buffer, Tris(Hydroxymethyl)Aminomethane (TRIS) is not only widely used as a solvent for nucleic acids and proteins, but also as one of the main components of protein electrophoresis buffers. It can also produce a variety of chemicals and pesticides, pharmaceutical products, and it is an important intermediate for the preparation of surfactants, vulcanization accelerators and some drugs. This article will introduce another role of TRIS——modified zein functional drug-loaded microspheres.

As a natural hydrophobic macromolecule, zein has a wide range of sources, it is non-toxic, non-immunogenic, and has good biocompatibility and biodegradability. It is one of the few hydrophobic biopolymers that are allowed to be taken orally by the FDA：

(1) Its amino acid composition is very special, the proportion of non-polar amino acids is more than 50%. It can embed various substances such as polysaccharides. DNA, RNA, proteins, metal nanoparticles, quantum dots, oil droplets, and hydrophobic drugs;

(2) The amino acid residues on zein carry certain polar groups (such as ‐SH, ‐COOH, ‐NH3, and ‐OH), it provides the possibility to graft various functional molecules for chemical reaction sites and adapt to the complex and varied human environment.

Therefore, zein is an advantageous drug carrier material. However, the proportion of sulphur-containing amino acids in zein is only 2.8%, the ratio of basic amino acids is only 2.9%, and the proportion of hydroxyamino acids is 13.4%, which limits the selection of functional molecules and the effect of modification. To improve this, the researchers modified it with TRIS, including the following steps [1]:

(1) The zein and the amino protecting agent di-tert-butyl dicarbonate are dissolved in a specific dimethyl sulfoxide or ethanol aqueous solution at a mass ratio of 1:1~1.5:1, and protected from light at 25~40°C. The reaction is carried out for 12~24 hours to obtain a zein protection solution;

(2) Under the protection of nitrogen, add carbodiimide salt, N-hydroxysuccinimide and TRIS (CAS 77-86-1) to the zein protection solution, and avoid the light reaction at 25-40°C for 12~24 hours. To obtain a TRIS-zein solution;

(3) under the protection of nitrogen, adding concentrated hydrochloric acid to the tris-zein solution, and avoiding light reaction at 25-40°C for 6-8h;

(4) adjusting the pH to 5.0~6.0, transferring to a dialysis bag, centrifuging the retained solution in the dialysis bag, and lyophilizing to obtain TRIS-zein;

(5) Dissolving the hydrophobic drug and the lyophilized TRIS -zein in an aqueous solution of ethanol at a mass ratio of 1:1 to 1:10; and injecting hydrochloric acid having a pH of 2.5 to 4.5 under magnetic stirring. In the aqueous solution, after stabilization, the supernatant is centrifuged to obtain a drug-loaded microsphere;

(6) Functional modification of drug-loaded microspheres: separately prepare solutions containing different functional molecules, disperse the drug-loaded microspheres into a solution containing functional molecules, stir the reaction, centrifuge to remove the supernatant, and obtain functional drug carrying microsphere. The drug microspheres have a particle size of 100~300 nm and a drug-loading efficiency of 81.48~86.01%, and the grafting amount of the functional molecules is 1.72~1.94 times that of the unmodified zein microspheres.

The coupling of TRIS to zein significantly improves the physicochemical properties of zein. The prepared microspheres have good sphericity, uniform particle size distribution, high drug-loading efficiency, and are suitable for in vivo delivery. This research expands the application of zein in drug delivery systems and has a good application prospect in the field of medicine.

References

[1] Jiang Yanbin, Pang Jiafeng, Lu Shan, Li Zhixian, Trimethylolamine modified zein functional drug-loaded microspheres and preparation method. 2018, CN108403662A.

Edited by Suzhou Yacoo Science Co., Ltd.