15080-84-9Relevant articles and documents
Transmucosal delivery of methionine enkephalin. I: Solution stability and kinetics of degradation in various rabbit mucosa extracts
In Koo Chun,Chien
, p. 373 - 378 (1993)
To evaluate the feasibility of transmucosal delivery of methionine enkephalin (Tyr-Gly-Gly-Phe-Met; Met-Enk), it is important to first investigate its physicochemical and enzymatic stability. The kinetics of degradation of Met-Enk in aqueous solution was determined at pH 2.01-9.84 and 37-45 °C by high-performance liquid chromatography. The first-order rate constant (k) was calculated, and the log k-pH profile showed that Met-Enk is most stable at pH ~5.0. Various mucosae excised from rabbit were mounted on Valia-Chien permeation cells and exposed to isotonic phosphate buffer at physiologic pHs. Mucosal and serosal extracts were collected from the donor and receptor solutions, respectively. The degradation of Met-Enk in the extracts followed first-order kinetics, but no significant difference in the degradation rates was observed between mucosal and serosal extracts, regardless of the type of mucosa used. Degradation was most rapid in the extracts of rectal mucosa, followed by vaginal and nasal mucosae. The major metabolites were Des-Tyr-Met-Enk and Tyrosine (Tyr), indicating the enzymatic hydrolysis by aminopeptidases. However, the data also suggested that dipeptidyl peptidase and dipeptidyl carboxypeptidase could play some roles in the degradation of Met-Enk. The degradation pathways of Met-Enk were further explored by concomitantly determining the formation of smaller metabolites of primary hydrolytic fragments of Met-Enk in the mucosal extracts.
Peptide bond formation by aminolysin-A catalysis: A simple approach to enzymatic synthesis of diverse short oligopeptides and biologically active puromycins
Usuki, Hirokazu,Yamamoto, Yukihiro,Arima, Jiro,Iwabuchi, Masaki,Miyoshi, Shozo,Nitoda, Teruhiko,Hatanaka, Tadashi
, p. 2327 - 2335 (2011/05/02)
A new S9 family aminopeptidase derived from the actinobacterial thermophile Acidothermus cellulolyticus was cloned and engineered into a transaminopeptidase by site-directed mutagenesis of catalytic Ser491 into Cys. The engineered biocatalyst, designated aminolysin-A, can catalyze the formation of peptide bonds to give linear homo-oligopeptides, hetero-dipeptides, and cyclic dipeptides using cost-effective substrates in a one-pot reaction. Aminolysin-A can recognize several C-terminal-modified amino acids, including the l- and d-forms, as acyl donors as well as free amines, including amino acids and puromycin aminonucleoside, as acyl acceptors. The absence of amino acid esters prevents the formation of peptides; therefore, the reaction mechanism involves aminolysis and not a reverse reaction of hydrolysis. The aminolysin system will be a beneficial tool for the preparation of structurally diverse peptide mimetics by a simple approach.
Enkephalin analogs containing the dipeptide unit Tyr-Arg (Kyotorphin)
Kubota,Nagase,Amano,Takagi,Yajima
, p. 2580 - 2586 (2007/10/02)
-
