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Amino Acid Reference Chart

A reference chart for the 20 human amino acids and associated properties. 

Code (1): Refers to each amino acid’s single letter code

Code (3): Refers to each amino acid’s three letter code

pKa: Refers to the negative logarithm of thedissociation constant for the functional group of the amino acid. Also known asthe pH below which the group is protonated. This can change based on the environment of the amino acid.

pI: Refers to the pH at the amino acid isoelectric point

Property: Often divided into “polar” and “nonpolar” groups; here we provided a more descriptive note on the amino acid functional group chemical and charge properties.

Essential: Refers to whether the amino acid must be obtained from the diet (essential) or can be synthesized in the body (non-essential).

Name Code (1) Code (3) pKa pI Property Essential
Alanine Ala A   6.00 Alipathic Non-essential
Asparagine Asn N   5.41 Amidic Non-essential
Asp D 3.65 2.77 Acidic Non-essential
Arginine Arg R 12.48 10.76 Basic Non-essential
Cysteine Cys C   5.07 Sulfuric Non-essential
Glu E 4.25 3.22 Acidic Non-essential
Glutamine Gln Q   5.65 Amidic Non-essential
Glycine Gly G   5.97 Alipathic Non-essential
Histidine His H 6.00 7.59 Basic Essential
Isoleucine Ile I   6.02 Alipathic Essential
Lysine Lys K 10.53 9.74 Basic Essential
Leucine Leu L   5.98 Alipathic Essential
Methionine Met M   5.74 Sulfuric Essential
Phe F   5.48 Aromatic Essential
Proline Pro P   6.30 Alipathic Non-essential
Serine Ser S   5.68 Hydroxylic Non-essential
Threonine Thr T   5.60 Hydroxylic Essential
Trp W   5.89 Aromatic Essential
Tyrosine Tyr Y 10.07 5.66 Aromatic Non-essential
Valine Val V   5.96 Alipathic Essential

Codon Chart

A reference codon chart for the three-letter RNA codes and their corresponding amino acids. Below are the nucleotides and their abbreviations, followed by amino acids and their full name, three letter code, and single letter abbreviations.    2nd position         1st position U C A G 3rd position U Phe Ser Tyr… Continue Reading

Common Scientific Constants

A reference chart of some common physical and mathematical constants. Physical  & Mathematical Constants     Atmosphere (standard) atm 101.325 × 103 Pa Atomic mass unit (Dalton) amu 1.661 × 10-24 g Avogadro’s number N 6.022 × 1023/mol Base of natural log e 2.718 Becquerel Bq 1 dps Boltzmann constant k 1.381 × 10-23 J/K… Continue Reading

Scientific Unit Abbreviations

A reference table of scientific units and their abbreviations as well as some prefixes used in the international system of units.  Unit Abbreviations A ampere Å angstrom atm atmosphere Bq becquerel C coulomb °C Celsius, centigrade cal calorie cc cubic centimeter Ci, c Curie cm centimeter cpm counts per minute Da dalton dam decameter dB… Continue Reading

Pharmacology Abbreviations

A reference table for commonly used pharmacology terms and abbreviations. Drugs   ACD Anticonvulsant drug ACR Adverse drug reaction ASA Acetylsalicyclic acid (aspirin) CD Curative dose D, dos Dose, dosage DAW Dispense as written DAWN Drug Abuse Warning Network DIG Digitalis DSB Drug-seeking behavior IND Investigational new drug INH Isoniazid (TB drug) LD Lethal dose… Continue Reading

Citations and References: Altogen Transfection Products

Citations and References: Altogen® Transfection Reagents Nature Medicine 2016 22(10):1131–1139. A Long Non-Coding RNA Defines an Epigenetic Checkpoint … Wang et al [PDF] Nature 2008 454(7203):523-7. Innate immunity induced by composition-dependent RIG-I …Saito et al [PDF] Molecular Therapy 2018. Liposome Lipid-Based Formulation … Guo et al [PDF] J Cereb Blood Flow Metab 2017. Inhibition of… Continue Reading

cGMP-grade Nanoparticle Transfection Reagent for In Vivo Delivery

Altogen Biosystems is a manufacturer of life science research products that includes in vivo transfection reagents designed for tissue-targeted delivery of biomolecules. Altogen’s Nanoparticle In Vivo Transfection Reagent was launched in 2008 and used in over 30 research publications demonstrating highly efficient delivery of cargo nucleic acids (siRNA, microRNA, mRNA, plasmid DNA, and small proteins)… Continue Reading

AltoFect v2.0 second generation transfection reagent

AltoFect v2.0, the second generation transfection reagent for primary cell types and hard-to-transfect cell lines. AltoFect transfection reagent exhibits up to 85% transfection efficiency in difficult-to-transfect cells such as T-cells, B-cells, and primary cell cultures. The advance has opened up the path to reliable in vitro testing of realistic responses from cells that were previously… Continue Reading

AltoFect Transfection Reagent for Primary Cells and Hard-to-transfect Cell Lines

Altogen Biosystems developed AltoFect™ Transfection Reagent – a new generation transfection reagent optimized for high transfection efficiency of primary cells and difficult-to-transfect cell lines. It has been successfully tested to deliver all types of nucleic acids (plasmid DNA constructs, si/miRNA, shRNA, dsRNA, mRNA, etc), small proteins, and negatively charged small molecules. Cancer cell lines and primary cell types, a… Continue Reading

CRISPR/Cas9 Transfection Optimization

Efficient delivery of the CRISPR/Cas9 protein complex can be achieved efficiently through the use of cationic lipid-based transfection reagents. Cells may undergo electroporation to increase the probability of successful transfection. Once inside a target cell, the CRISPR/Cas9 protein complex requires no additional stimulation to start modifying the cell’s genome. Genome modification will occur within one… Continue Reading

Where to purchase cancer cell lines?

Cancer cell lines must be purchased from trustworthy vendors (i.e. ATCC, Sigma-Aldrich, DSMZ), along with signing licenses and agreements.  These large cell bank vendors have established good quality control processes, document controls and facilities that are able to offer well characterized cell lines. Continue Reading

Caspase-3/7 cell line screen for test compound

Caspase 3/7 activity is a cell based assay that measures apoptosis.  Commercially available reagents enable high-throughput screening of apoptosis inducing test compounds or contract research organizations can readily perform the compound screening.  A brief overview of the protocol is as follows: Cells in logarithmic growth are seeded in a 96-well plate Depending on the scope… Continue Reading

Tissue culture using flasks vs dishes for cell lines

Flasks and dishes that are cell culture coated are both acceptable consumables to use for cell culture.  Employing sterile techniques allows an experienced scientist to use either item, with pros and cons listed here for each system. Filtered Flasks Narrow opening translates to a lesser chance of contaminant entering the flask Ideal for long term… Continue Reading

Cell passage: How to correctly dilute and split cultured cells

There are many different cell culture techniques. Utilizing correct cell passaging methods is important to keep cell line in exponential growth curve, therefore making it a good model as a host for transfection experiments. “Cell passage” is a term used by other scientists to demonstrate the following process: Wash cells with PBS Detach cells from… Continue Reading

How to ship cells as a live culture?

Shipping cells to collaborators can be accomplished by either sending them a frozen aliquot on dry ice or by sending a live culture.  Sending a live culture has the advantages of the cells continuing their exponential growth to aid in timing of experiments.  This is accomplished by completely filling the flask with culture medium, closing… Continue Reading

How to determine cell viability?

Cell viability is a calculation of the number of viable or living cells within the total number of cells.  Although there are now commercially available alternatives to the historical method, trypan blue exclusion is the tried and true method commonly used in the lab.  Briefly, trypan blue dye is added to a cell suspension and… Continue Reading

How to determine mycoplasma contamination?

Mycoplasma contamination is a common occurrence and labs must be vigilant in monitoring and combating contamination issues.  Mycoplasma are bacteria extremely difficult to detect in cultured cells by visual inspection.  Many labs do not incorporate recurring mycoplasma testing until the lab experiences a contamination incident, at which time cleaning and testing procedures are put in… Continue Reading

Even cell distribution in the 6-well plate instead of a ring of cells around the edges?

Performing cell culture experiments in round well plates can often lead to troubling spatial dispersion of the cells.  This can be attributed to culture incubators having high vibrations, non-level incubators or bad practices such as swirling the plate after adding cells.  In order to achieve even distribution of cells in the wells of culture plates,… Continue Reading

Is it necessary to synchronize cells?

Exponentially growing cultured cells are growing at difference cell cycle stages, termed asynchronous.  Scientists are vigilant in their techniques to ensure they are using non-confluent cells prior to their experiments; thus, synchronization is not commonly employed.  However, synchronizing your cells can help improve the results of certain cell based assays such as viral integration or… Continue Reading

Low cell viability due to the freezing or thawing of cancer cell lines

Freeze slow, thaw fast.  The process of freezing and thawing cancer cell lines requires extreme attention to protocol.  For freezing, a good freezing media that contains DMSO is added to the correct number of cells following the manufacturer’s instructions.  The vital part of the freezing process is to ensur that the freezing process is slow. … Continue Reading