Search results for "serine"
showing 10 items of 590 documents
Selektivit�tsstudien: OH-, NH- und SH-gruppenspezifische Reagentien - ihre Anwendung in der organischen Analytik und als Schutzgruppen in der Synthese
1992
Selectivity: OH-, NH- and SH-Groupspecific Reagents. The Application in Organic Analysis and as Protective Groups Phosphylhalides and -pseudohalides R1R2P(O)X (X = Cl, F, CN, N3, OC6H4NO2(p)) reactdepending on X- with a different selectivity with OHNH- and SH-groups. Vinylsulfones ArSO2CH = CH2 are SH-selective. Silanes R3SiH are OH-selective. By exchange of one ligand bound on P, SO2 or Si by the 5-dimethylamino resp. the 5-methoxynaphthalinogroup reagents are formed, which combine group selectivity with fluorescence. The fluorescence is quenched if a ligand or the leaving group is substituted by a NO2-group. The fluorescence appears again if after the group selective fixation the ligand w…
Plastidial Glycolytic Glyceraldehyde-3-Phosphate Dehydrogenase Is an Important Determinant in the Carbon and Nitrogen Metabolism of Heterotrophic Cel…
2015
This study functionally characterizes the Arabidopsis (Arabidopsis thaliana) plastidial glycolytic isoforms of glyceraldehyde-3-phosphate dehydrogenase (GAPCp) in photosynthetic and heterotrophic cells. We expressed the enzyme in gapcp double mutants (gapcp1gapcp2) under the control of photosynthetic (Rubisco small subunit RBCS2B [RBCS]) or heterotrophic (phosphate transporter PHT1.2 [PHT]) cell-specific promoters. Expression of GAPCp1 under the control of RBCS in gapcp1gapcp2 had no significant effect on the metabolite profile or growth in the aerial part (AP). GAPCp1 expression under the control of the PHT promoter clearly affected Arabidopsis development by increasing the number of later…
Chemoselektive Fluoreszenzstudien am Subtilisin und “Thiosubtilisin”
1985
Chemoselective Fluorescence Studies with Subtilisin and “Thiosubtilisin” The serine hydroxy group in the active site of subtilisin is selectively “phosphylated”3). This is demonstrated using the fluorescent phosphinic fluoride 1. “Thiosubtilisin” does not react with 1 but with the SH-selective and fluorescent vinyl sulfone 2.
A novel phosphorus–carbon bond formation by ring opening with diethyl phosphite of oxazolines derived from serine
2004
Abstract A new reaction of oxazolines derived from serine with diethyl phosphite leading to ring opening products with P–C bond formation is reported. This reaction, which proceeds under neutral conditions and without the use of any halogenated intermediate, results in a mixture of racemic α- and β-phosphono alanines in an approximate 1:2 ratio, with isolated yields up to 77%. The mechanism involves the rearrangement of the oxazoline into the corresponding α-benzamido acrylate, followed by addition of the diethyl phosphite to the double bond. Since no significant transesterification is observed, this method constitutes a simple route for α- and β-phosphono amino acids bearing suitable prote…
Carbamate Linker Strategy in Solid-Phase Synthesis of Amino-Functionalized Glycoconjugates for Attachment to Solid Surfaces and Investigation of Prot…
2009
Amino-functionalized serine-based galactose and glucose neoglycolipids were prepared by solid-phase synthesis using a carbamate strategy for anchoring amino functionalities to a (2-fluoro-4-hydroxy ...
Posttranslational processing of human alpha 2-HS glycoprotein (human fetuin). Evidence for the production of a phosphorylated single-chain form by he…
1994
alpha 2-HS glycoprotein (alpha 2-HS) is a major protein occurring in human blood and calciferous tissues. Due to extensive sequence identity, alpha 2-HS has been grouped with the fetuins, a family of proteins that occur in fetal plasma in high concentrations. Native alpha 2-HS undergoes a series of posttranslational modifications including proteolytic processing, multiple N-glycosylations and O-glycosylations, and sulfation of the carbohydrate side chains. Various two-chain forms of alpha 2-HS have been prepared from human plasma, however, the single-chain precursor has not yet been isolated. Here, we have studied the biosynthesis of alpha 2-HS by a human hepatoma cell line, HepG2. We demon…
Fluorenylmethoxycarbonyl-ProtectedO-Glycosyl-N-methyl Amino Acids: Building Blocks for the Synthesis of Conformationally Tuned Glycopeptide Antigens
2015
Peptide antibiotics often contain N-methylated amino acids. These N-methylamino components enhance the metabolic stability and strongly influence the conformational behavior of these peptide drugs. N-Methyl-O-glycosyl amino acids, in particular, threonine and serine derivatives, are unknown so far. Fmoc-protected N-methyl-O-glycosyl-threonine and -serine building blocks, including sialyl TN antigens, have been synthesized for the first time by converting the Fmoc-protected O-glycosyl amino acids or their tert-butyl esters into the corresponding oxazolidinones followed by reductive ring-opening. These new components are considered interesting for the construction of modified mucin glycopepti…
Synthese von Giycopeptiden: Selektive C-terminale Deblockierung und Peptidkettenverlängerung an Glucosylserin-Derivaten
1983
Benzyloxycarbonyl-(Z-)serin-2-bromethylester (3b) wird mit 2,3,4,6-Tetra-O-benzoyl-α-D-gluco-pyranosylbromid (14) zum Glucosylserinester 15 verknupft. Nach Umwandlung in den entsprechenden 2-Iodethylester 23 wird die Carboxygruppe durch Eliminierung mit Zink selektiv deblockiert. Dabei bleiben die Z- und die Kohlenhydrat-Schutzgruppen sowie die empfindliche O-glycosidische Bindung unverandert erhalten. Das Glycosyl-Z-serin 24 reagiert mit Aminosaure-2-bromethylestern 2 zu geschutzten Glycodipeptid-2-bromethylestern 18, die nach selektiver Carboxydeblockierung zu Glycotripeptidestern 25 C-terminal verlangert werden. Wahrend geschutzte Serin-Dipeptide 5 mit 14 zu Konjugaten 18 glycosyliert we…
Enzymatic glycosylation of o-glycopeptides
1992
Abstract O-Glycosylation of serine derivatives carried out with N-urethane protected glucosamine yields O-glycopeptides which are regio- and stereoselectively galactosylated with the aid of β-1,4-galactosyltransferase (EC 2.4.1.22).
Posttranslational Processing of Human α2-HS Glycoprotein (Human Fetuin)
2008
α2-HS glycoprotein (α2-HS) is a major protein occuring in human blood and calciferous tissues. Due to extensive sequence identity, α2-HS has been grouped with the fetuins, a family of proteins that occur in fetal plasma in high concentrations. Native α2-HS undergoes a series of posttranslational modifications including proteolytic processing, multiple N-glycosylations and O-glycosylations, and sulfation of the carbohydrate side chains. Various two-chain forms of α2-HS have been prepared from human plasma, however, the single-chain precursor has not yet been isolated. Here, we have studied the biosynthesis of α2-HS by a human hepatoma cell line, HepG2. We demonstrate that a single-chain form…