N-Acetyl-D-isoleucine

The crystal structures of N-acetyl-DL-isoleucine, N-acetyl-DL-alloisoleucine and their ammonium salts show that these four compounds exist as racemic compounds around room temperature. The two ammonium salts are arranged around a 21 screw axis, forming a helical column which consists of ammonium ions and single enantiomeric anions similar to the crystals of the ammonium salts of optically active N-acetyl-L-isoleucine and N-acetyl-D-alloisoleucine. The ammonium ion and the carboxylate ion in the helix are connected by three hydrogen bonds, the fourth hydrogen bond being formed between the ammonium ion and an external acetyl amino group of the neighboring helical column. The fourth hydrogen bond is formed between the ammonium ion and an external acetyl amino group of the neighboring 21 column. Ammonium N-acetyl-DL-alloisoleucinate was revealed to exist as an unstable racemic compound due to conformational similarity between the racemic and optically active compounds in the solid state and was optically resolved by fractional crystallization at 293 K.

Salinity hinders agricultural productivity worldwide by distressing plant metabolism. Growth of blackgram (Vigna mungo L. var. Sulata), an adverse climate-resistant pulse, is arrested under salinity. Present research integrates study of physio-biochemical parameters and non-targeted metabolomics approach to explore the alterations in metabolic pathway during adaptive responses of nonprimed and haloprimed blackgram seedlings grown hydroponically under NaCl stress. Salinity provoked accumulation of peroxides, compatible solutes and phenolics which increased free radical scavenging activities of nonprimed seedlings under salinity. Pre-germination seed halopriming abrogated NaCl-mediated adversities in haloprimed plantlets favouring better growth. Thus, farmers may adopt seed halopriming technique to improve blackgram productivity in saline-prone fields. Additionally, metabolomics study uncovered numerous metabolites amongst which 35 compounds altered significantly under salinity. The candidate metabolites were aspartic acid, L-glutamic acid, L-proline, L-asparagine, DL-isoleucine, L-homoserine, citrulline, L-ornithine, D-altrose, D-allose, N-acetyl-D-mannosamine, fructose, tagatose, sucrose, D-glucose, maltose, glycerol-1-phosphate, D-sorbitol, benzoic acid, shikimic acid, 4-hydroxycinnamic acid, arbutin, succinic acid, pipecolic acid, fumaric acid, nicotinic acid, L-pyroglutamic acid, oxalic acid, glyceric acid, maleamic acid, adenine, guanosine, lauric acid, stearic acid and porphine. Comparing metabolic responses of nonprimed and haloprimed seedlings, it was clear that efficient alteration in carbohydrate metabolism, phenolics accumulation, amino acid, organic acid and nucleic acid metabolism were the key places of metabolic reprogramming for tolerating salinity. Overall, we report, for the first time, 35 contributory candidate compounds that constituted core fundamental metabolome invoking salinity tolerance in nonprimed and haloprimed blackgram. These metabolites may be targeted by biotechnologists to produce high vigour salt-tolerant transgenic blackgram via genetic engineering.

Background: Branched-chain amino acids (BCAAs; isoleucine, leucine, and valine) correlate with insulin resistance and poor glucose control, which may in part explain associations between type 2 diabetes and cardiovascular disease. However, the relationships of BCAAs with other cardiometabolic pathways, including inflammation and dyslipidemia, are unclear. We hypothesized that plasma BCAAs would correlate with multiple pathways of cardiometabolic dysfunction. Methods: We conducted a cross-sectional analysis among 19 472 participants (mean age=54.9 years, SD=7.2 years) in the Women's Health Study without a history of type 2 diabetes, cardiovascular disease, or cancer. We quantified the concentrations of individual biomarkers of inflammation and lipids, across quartiles of BCAAs, adjusting for age, smoking, body mass index, physical activity, and other established cardiovascular disease risk factors at blood draw. Results: Women in the highest versus lowest quartiles of plasma BCAAs had higher inflammatory markers including high-sensitivity C-reactive protein (multivariable-adjusted means: 1.96 versus 1.43 mg/L), fibrinogen (367 versus 362 mg/dL), soluble intercellular cell adhesion molecule-1 (361 versus 353 ng/mL), and glycoprotein acetylation (407 versus 371 µmol/L; P trend=0.0002 for fibrinogen; P<0.0001 for others). Similarly for lipids, women with higher BCAAs had lower HDL-C (high-density lipoprotein cholesterol; 49.0 versus 55.0 mg/dL), and higher triglycerides (143 versus 114 mg/dL), LDL-C (low-density lipoprotein cholesterol; 133 versus 124 mg/dL), and lipoprotein insulin resistance score (52.6 versus 37.3; all: P<0.0001). Similar associations with these biomarkers were observed in isoleucine, leucine, and valine, respectively. Conclusions: Higher circulating BCAA concentrations are associated with adverse profiles of biomarkers of inflammation and dyslipidemia independent of established cardiovascular disease risk factors, and thus, may reflect poorer cardiometabolic health through multiple pathways. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00000479.