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Cellulosic ethanol could play a major role in the upcoming circular-economy once the process complexity, low carbohydrate extraction yields and high costs are resolved. To this purpose, different steam-treatment severity factors were employed on whole sweet sorghum biomass, followed by the delignification and hydrolysis of resulted lignocellulose fibers. A modified ASTM International (American Society for Testing and Material) standard cellulose hydrolysis approach as well as a newly developed SACH (Sulfuric Acid Cellulose Hydrolysis) process were used, recovering up to 24.3 wt% of cellulosic carbohydrates. This amounted to a total extractable and constitutive carbohydrate recovery of 51.7 wt% (dry basis) when a mild steam-treatment of whole sorghum biomass and the SACH cellulose hydrolysis were employed. An ethanol potential of 6378 L/ha/year was determined, comparable to values obtained from biomass such as sugarcane in warmer climates, supporting thus the opportunity of implementing this novel approach on a wider scale.

Maximizing the extracted carbohydrates from lignocellulosic biomass represents one critical step towards a wide implementation of industrial-scale second-generation ethanol production. To this purpose, a novel steam-based treatment strategy targeting the whole sweet sorghum biomass was developed. This extraction was followed by a non-enzymatic hydrolysis of the hemicellulose fraction and ethanol fermentation. By doing so, both the free carbohydrates present in the plant stems as well as the hemicelluloses trapped inside the various structural components were recovered and converted. A statistical design of experiments (DoE) approach was developed to investigate the most suitable steam-treatment severity to maximize the recovery of these carbohydrates while simultaneously minimizing the production of fermentation inhibitors. The severity of the treatment was estimated from the combined effects of temperature (150 °C – 210 °C) and cooking time (1–7 min). The optimal treatment conditions identified in this work (3 min retention time at 180 °C) successfully allowed recovering 30% of monomeric carbohydrates (based on sorghum dry weight). Three of the most efficient steam-explosion severities were investigated further in order to evaluate their impact on the subsequent ethanol fermentation using Saccharomyces cerevisiae yeast. A maximum ethanol yield of above 95% was achieved using the mixed carbohydrate streams recovered using the optimal steam-based extraction conditions. Thus, the present work thoroughly describes for the first time and to the best of our knowledge, a single-stage recovery of sorghum extractives and hemicelluloses, followed by their efficient fermentation to ethanol.

PACE4 plays an important role in the progression of prostate cancer and is an attractive target for the development of novel inhibitor-based tumor therapies. We previously reported the design and synthesis of a novel, potent, and relatively selective PACE4 inhibitor known as a Multi-Leu (ML) peptide. In the present work, we examined the ML peptide through detailed structure-activity relationship studies. A variety of ML-peptide analogues modified at the P8-P5 positions with leucine isomers (Nle, DLeu, and DNle) or substituted at the P1 position with arginine mimetics were tested for their inhibitory activity, specificity, stability, and antiproliferative effect. By incorporating d isomers at the P8 position or a decarboxylated arginine mimetic, we obtained analogues with an improved stability profile and excellent antiproliferative properties. The DLeu or DNle residue also has improved specificity toward PACE4, whereas specificity was reduced for a peptide modified with the arginine mimetic, such as 4-amidinobenzylamide.

A new method for solid phase parallel synthesis of chemically and conformationally diverse macrocyclic peptidomimetics is reported. A key feature of the method is access to broad chemical and conformational diversity. Synthesis and mechanistic studies on the macrocyclization step are reported.

PACE4 plays important roles in prostate cancer cell proliferation. The inhibition of this enzyme has been shown to slow prostate cancer progression and is emerging as a promising therapeutic strategy. In previous work, we developed a highly potent and selective PACE4 inhibitor, the multi-Leu (ML) peptide, an octapeptide with the sequence Ac-LLLLRVKR-NH2 . Here, with the objective of developing a useful compound for in vivo administration, we investigate the effect of N-terminal modifications. The inhibitory activity, toxicity, stability, and cell penetration properties of the resulting analogues were studied and compared to the unmodified inhibitor. Our results show that the incorporation of a polyethylene glycol (PEG) moiety leads to a loss of antiproliferative activity, whereas the attachment of a lipid chain preserves or improves it. However, the lipidated peptides are significantly more toxic when compared with their unmodified counterparts. Therefore, the best results were achieved not by the N-terminal extension but by the protection of both ends with the d-Leu residue and 4-amidinobenzylamide, which yielded the most stable inhibitor, with an excellent activity and toxicity profile.

Proprotein convertases (PCs) are crucial in the processing and entry of viral or bacterial protein precursors and confer increased infectivity of pathogens bearing a PC activation site, which results in increased symptom severity and lethality. Previously, we developed a nanomolar peptide inhibitor of PCs to prevent PC activation of infectious agents. Herein, we describe a peptidomimetic approach that increases the stability of this inhibitor for use in vivo to prevent systemic infections and cellular damage, such as that caused by influenza H5N1 and Shiga toxin. The addition of azaβ(3)-amino acids to both termini of the peptide successfully prevented influenza hemagglutinin 5 fusogenicity and Shiga toxin Vero toxicity in cell-based assays. The results from a cell-based model using stable shRNA-induced proprotein convertase knockdown indicate that only furin is the major proprotein convertase required for HA5 cleavage.

The methanolysis of allylic alcohols, benzylic tertiary alcohols and epoxides in the presence of a catalytic amount of ceric ammonium nitrate (CAN) is shown to be catalysed by protons generated from the oxidation of methanol. This reaction is also catalysed by Lewis acids.

High-throughput screening of Tranzyme Pharma's proprietary macrocycle library using the aequorin Ca2+-bioluminescence assay against the human ghrelin receptor (GRLN) led to the discovery of novel agonists against this G-protein coupled receptor. Early hits such as 1 (Ki=86 nM, EC50=134 nM) though potent in vitro displayed poor pharmacokinetic properties that required optimization. While such macrocycles are not fully rule-of-five compliant, principally due to their molecular weight and clogP, optimization of their pharmacokinetic properties proved feasible largely through conformational rigidification. Extensive SAR led to the identification of 2 (Ki=16 nM, EC50=29 nM), also known as ulimorelin or TZP-101, which has progressed to phase III human clinical trials for the treatment of postoperative ileus. X-ray structure and detailed NMR studies indicated a rigid peptidomimetic portion in 2 that is best defined as a nonideal type-I' β-turn. Compound 2 is 24% orally bioavailable in both rats and monkeys. Despite its potency, in vitro and in gastric emptying studies, 2 did not induce growth hormone (GH) release in rats, thus demarcating the GH versus GI pharmacology of GRLN.

A novel class of macrocyclic peptidomimetics was identified and optimized as potent antagonists to the human motilin receptor (hMOT-R). Well-defined structure-activity relationships allowed for rapid optimization of potency that eventually led to high affinity antagonists to hMOT-R. Potency and antagonist functional activity were confirmed both in functional and cell-based assays, as well as on isolated rabbit intestinal smooth muscle strips. Rapid access to this novel class of macrocyclic target structures was made possible through two efficient and complementary solid-phase parallel synthetic approaches, both of which are reported herein.