31982-10-2Relevant articles and documents
Influence of Sulfur-Containing Diamino Acid Structure on Covalently Crosslinked Copolypeptide Hydrogels
Raftery, Eric D.,Gharkhanian, Eric G.,Ricapito, Nicole G.,McNamara,Deming, Timothy J.
, p. 3547 - 3553 (2018/09/25)
Biologically occurring non-canonical di-α-amino acids were converted into new di-N-carboxyanhydride (di-NCA) monomers in reasonable yields with high purity. Five different di-NCAs were separately copolymerized with tert-butyl-l-glutamate NCA to obtain covalently crosslinked copolypeptides capable of forming hydrogels with varying crosslinker density. Comparison of hydrogel properties with residue structure revealed that different di-α-amino acids were not equivalent in crosslink formation. Notably, l-cystine was found to produce significantly weaker hydrogels compared to l-homocystine, l-cystathionine, and l-lanthionine, suggesting that l-cystine may be a sub-optimal choice of di-α-amino acid for preparation of copolypeptide networks. The di-α-amino acid crosslinkers also provided different chemical stability, where disulfide crosslinks were readily degraded by reduction, and thioether crosslinks were stable against reduction. This difference in response may provide a means to fine tune the reduction sensitivity of polypeptide biomaterial networks.
Syntheses of S-Substituted L-Homocysteine Derivatives by Cystathionine γ-Lyase of Streptomyces phaeochromogenes
Kanzaki, Hiroshi,Kobayashi, Michihiko,Nagasawa, Toru,Yamada, Hideaki
, p. 391 - 398 (2007/10/02)
Cystationine γ-lyase from Streptomyces phaeochromogenes catalyzes not only the α,γ-elimination rection of L-cystathionine, but also the γ-replacement reaction of L-homoserine in the presence of thiol compounds.Substrates for the enzyme in the γ-replacement reaction were examined.It was found that D-cysteine, L- and D-homocysteine, and 3- and 2-mercaptopropionate served as preferable substrates in the γ-replacement reaction.D-Allocystathionine, L- and mesohomolanthionine, S-carboxyethyl-L-homocysteine and S-methylcarboxymethyl-L-homocysteine were enzymatically synthesized from L-homoserine and the corresponding thiol compounds.The thus synthesized S-substituted L-homocysteine derivatives were isolated from large scale reaction mixtures and identified physicochemically.
