71591-21-4

Upstream product

• 687-51-4 H-L-Leu-NH₂ 
• 98254-08-1 Z-Tyr-Gly-Gly-Phe-OMe 
• 13512-31-7 N-(benzyloxycarbonyl)-L-tyrosine methyl ester 
• 82948-92-3 [des-tyr¹]-leucine enkephalinamide 
• 34695-67-5 Z-Tyr-Gly-Gly-OEt 
• 38678-59-0 L-Phe-L-Leu-NH₂ 
• 69193-13-1 Cbz-L-Phe-L-Leu-NH₂ 
• 69193-15-3 N-(benzyloxycarbonyl)-glycyl-L-phenylalanyl-L-leucine amide 
• 35909-92-3 N-carbobenzoxy-L-phenylalanine methyl ester 
• 84969-56-2 Z-Gly-Gly-L-Phe-L-Leu-NH₂ 
• 71591-20-3 H-Gly-Phe-Leu-NH₂ 
• 16679-94-0 N-[(phenylmethoxy)carbonyl]-L-tyrosine 

Relevant academic research and scientific papers

Encapsulation of biologicals within silicate, siloxane, and hybrid sol- gel polymers: An efficient and generic approach

The sol-gel encapsulation of labile biological materials with catalytic and recognition functions within robust polymer matrices remains a challenging task, despite the considerable research that has been focused on this field. Herein, we describe a new class of precursors, based around polyol silicates and polyol siloxanes, especially those derived from glycerol, that addresses problems faced with traditional bioencapsulation protocols. Poly(glyceryl silicate) (PGS) was prepared and employed for sol- gel bioentrapment, in an approach distinguished by a high biocompatibility and mild encapsulation conditions, and which enables the reproducible and efficient confinement of proteins and cells inside silica. The methodology was extended to metallosilicate, alkylsiloxane, functionalized siloxane, and composite sol-gels, thereby allowing the fabrication of a physicochemically diverse range of bio-doped polymers. The hybrid materials display activities approaching those of the free biologicals, together with the high stabilities and robustness that characterize sol-gel bioceramics. Indeed, the bioencapsulates performed better than those fabricated from tetramethoxysilane, poly(methyl silicate) or alcohol-free poly(silicic acid), even when the latter were doped with glycerol. The activity enhancements appear to derive at least in part from the unusual microstructure of PGS sol- gels, in particular their high porosity, although the underlying mechanisms are unclear. Differences in precursor hydrolysis/condensation; development of gel structure, biological-matrix interactions, precursor toxicity, and pore collapse probably all contribute to the observed efficiency of the PGS materials. The performances of the encapsulates are compared with conventional sol-biogels and other immobilizates, in representative biocatalyst, biosensor, and biodiagnostic applications.

Facile Enzymatic Synthesis of N-Acyl-enkephalin Amides

A novel three step protease catalysed synthesis of enkephalin precursors from simple readily available substrates is described.

Peptide Synthesis Mediated by Immobilized and Viable Baker's Yeast in Reverse Micelles: Synthesis of Leucine Enkephalin Analogues

Cells of baker's yeast (Saccharomyces cerevisiae NCIM 3305) immobilized in calcium alginate beads are found to be viable in reverse micelles of bis(2-ethylhexyl)sulphosuccinate sodium salt 1 in iso-octane for days and were used for the first time for pept

Enzymes in organic synthesis: Use of subtilisin and a highly stable mutant derived from multiple site-specific mutations

A subtilisin mutant (subtilisin 8350) derived from subtilisin BPN' via six-specific mutations (Met50Phe, Gly169Ala, Asn76Asp, Gln206Cys, Tyr217Lys, and Asn218Ser) was found to be 100 times more stable than the wild-type enzyme in aqueous solution at room temperature and 50 times more stable than the wild type in anhydrous dimethylformamide. Kinetic studies using ester, thio ester, and amide substrates, and the transition-state analogue inhibitor Boc-Ala-Val-Phe-CF3, indicate the both the wild-type and the mutant enzymes have very similar specificities and catalytic properties. The inhibition constant (K(i)) = 5.0 μM) for the wild-type enzyme is approximately 5 times that of the mutant enzyme (K(i)) = 1.1 μM), suggesting that the mutant enzyme binds the reaction transition state more strongly than the wild-type enzyme. This result is consistent with the observed rate constants for the corresponding ester and amide substrates; i.e. the k(cat)/k(m) values for the mutant are larger than those for hhe wild-type enzyme. Application of the mutant enzyme and the wild-type enzyme to organic synthesis has been demonstrated in the regioselective acylation of nucleosides in anhydrous dimethylformamide (with 65-100% regioselectivity at the 5'-position), in the enantioselective hydrolysis of N-protected and unprotected common and uncommon amino acid esters in water (with 85-98% enantioselectivity for the L-isomer), and in the synthesis of di- and oligopeptides via aminolysis of N-protected amino acid and peptide esters. The enzymatic peptide synthesis was carried out under high concentrations of DMF (~50%) to improve substrate solubility and to minimize enzymatic peptide cleavage. Low enantioselectivity was observed in the enzymatic transformation of non-amino acid alcohols and acids.

Papain Catalysed Peptide Synthesis: Control of Amidase Activity and the Introduction of Unusual Amino Acids

Procedures for the papain catalysed synthesis of peptides containing D-amino acids and derivatives with control of the enzyme's amidase activity have been developed.