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Finding a Target
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
Amino acids are di-functional, containing a basic amine group and acidic carboxyl group. Each of the 20 amino acids is an alpha-amino acid, in other words, the amine substituent is attached to the alpha carbon next to the carbonyl group. Also note that 19 of those amino acids are primary amino acids and only differ in the side chain substituent. Having both acidic and basic groups, amino acids are able to undergo internal acid-base reactions to produce dipolar ions, called zwitterions at a particular pH, known as the isoelectric point, and are amphoteric, acting as both an acid and a base, which is crucial for their involvement in biological catalysis. A polypeptide is synthesised from amino acids by the condensation reaction between the carboxylic acid group of one amino acid with the amino group of the next to form an amide linkage, or peptide bond, via an enzyme-controlled pathway.
Collagen Production by the Intestinal Smooth Muscle Cell in Response to Inflammation: Wound Healing in the Gut
Published in William J. Snape, Stephen M. Collins, Effects of Immune Cells and Inflammation on Smooth Muscle and Enteric Nerves, 2020
The collagen content of the bowel wall was determined by quantitating hydroxyproline in full-thickness samples taken with a 6 mm dermal trephine. Following acid hydrolysis and derivitisation, the total hydroxyproline content of each sample was determined by high performance liquid chromatography. The total alpha amino acid content of each sample was determined using a photometric ninhydrin assay.
Conditioning of Hair
Published in Dale H. Johnson, Hair and Hair Care, 2018
b. Proteins. Proteins serve many diverse biological functions acting as catalysts in enzymes, structural elements in bone collagen and hair keratin, nutrient storehouses in milk casein and egg ovalbumin, and many more. Proteins are made up of one or more polypeptide chains which in turn are made up of many alpha-amino acid residues linked together by a peptide bond. There are 20 different alpha-amino acids commonly found in proteins (42), listed in Table 2. All of these amino acids, except for proline, contain a free carboxyl group and a free unsubstituted amino group on the alpha-carbon. The amino acids differ from one another by their side chain R groups. Many amino acid residues are arranged in complex specific sequences to form proteins which range in molecular weight from about 5000 to over 1 million.
Dihydrofolate reductase inhibitors: patent landscape and phases of clinical development (2001–2021)
Published in Expert Opinion on Therapeutic Patents, 2022
Kavita Bhagat, Nitish Kumar, Harmandeep Kaur Gulati, Aanchal Sharma, Amandeep Kaur, Jatinder Vir Singh, Harbinder Singh, Preet Mohinder Singh Bedi
In 2007, scientists at Chroma Therapeutics extended their claims on pyrimidine derivatives as DHFR inhibitors for their use as anticancer, anti-inflammatory, and anti-microbial drugs. An important aspect of its invention is to the presence of an alpha amino acid ester group into the synthesized molecules, where its mode of attachment results in selective accumulation of DHFR inhibitors in specific cell types. This results into enhancement of potency as well as their duration of action because the ester group hydrolyzed and release the parent acid inside the cell. This results into enhancement of potency as well as their duration of action of the synthesized compounds. In this regard, biological evaluation of synthesized compounds (n = 10) was carried out against the DHFR enzyme, in which compound 5 (Table 2) exhibited significant potency (<100 nM) against hDHFR. These compounds were also subjected to cell inhibition assay against cancer cell lines (U937, HCT 116, THP, and HUT), and the results indicated that most of the compounds remarkably inhibited both U937 and HUT cell line [63].
Association between smoking status and homocysteine levels and possible effect modification by cholesterol and oestradiol
Published in Biomarkers, 2020
Ogbebor Enaholo Omoike, Timir K. Paul, Stanley L. Ridner, Manul Awasthi, Sam Harirforoosh, Hadii M. Mamudu
Homocysteine is an alpha amino-acid homologue of cysteine found in humans and formed from methionine by the removal of a methyl group at the terminal end (Joseph 2014). It potentiates oxidative reaction, inflammatory processes and creates an environment of procoagulative states causing endothelial dysfunction by atherogenic gene expressions (Hildebrandt et al.2015). Active cigarette smoking and second-hand tobacco smoking (SHS) exposure increase homocysteine levels (Mouhamed et al.2011). The exact mechanism by which active smokers and those exposed to SHS have higher levels of homocysteine is not known, although it might be due to a lower level of specific vitamins (Mouhamed et al.2011). Irrespective of the underlying reason(s), evidence indicates that elevated levels of homocysteine is associated with Alzheimer’s disease, birth defects, blood clots, cancer, coronary artery disease (CAD), dementia, endothelial damage, miscarriage, myocardial infarction, Parkinson’s disease, stroke and pre-eclampsia (Joseph 2014). These negative effects of elevated homocysteine on health outcomes suggest the importance of research into the impact of smoking and SHS exposure on homocysteine levels.
Bioactive cyclic molecules and drug design
Published in Expert Opinion on Drug Discovery, 2018
A potential problem is that pharmaceutical companies and to some extent, academic laboratories in the recent past, effectively ‘wedded themselves’ to the Lipinski ‘Rule of Five’ which eliminated the use of most peptides and related structures from contention, since a 4–5 residue amino-acid based structure would be close to or above the upper limit (500 Daltons) of the original RoF. Today, scientists have begun to realize that there is a significant gap in the molecular weight of drug candidates (the range from approximately 550 to 2000 Daltons) before one approaches the realm of biologics (roughly 4000+ Daltons). If one uses the approximation of 110 Daltons per average alpha amino-acid, then exploration of cyclic peptides (including peptide isosteres) that have structures based upon 5 to 18+ amino-acids is an area that should be further investigated.