摘要:
The present invention comprises a process for preparing insulin or an insulin derivative with correctly linked cysteine bridges from a precursor of said insulin or insulin derivative, wherein said precursor is subjected to a folding process in the presence of cysteine or cysteine hydrochloride and a chaotropic auxiliary compound. The insulin or insulin derivative with correctly linked cysteine bridges is obtained by enzymic cleavage by means of trypsin or a trypsin-like enzyme and, where appropriate, additionally by means of carboxypeptidase B and subsequent purification on an adsorber resin, which process is carried out at varied pH and temperature ranges.
摘要:
L-PTC (L-phosphinothricin, L-2-amino-4-methylphosphino-butyric acid) is the active herbicidal component of D,L-PTC and can be obtained according to the invention when D,L-PTC derivatives which are N-acylated and esterified on the phosphinic acid group as well as optionally esterified or amidated on the carboxylic group, are treated with a hydrolytically active enzyme in an aqueous or aqueous-organic medium, in which process the L-PTC derivatives are selectively hydrolyzed on the N-acyl group or the modified carboxyl group, the resulting product mixture is resolved, and the desired L-PTC derivative is hydrolyzed to give the L-PTC and isolated by customary methods.
摘要:
A process for highly regioselective esterification and ester cleavage on unsaturated sugar compounds with the aid of lipases and esterases, and products which can be prepared by this process.Highly regioselective esterifications and ester cleavages can be carried out on unsaturated sugar compounds with the aid of lipases and esterases. Lipases from microorganisms or from the pancreas and liver of animals are preferably used.
摘要:
Alkyl N-maleylphenylalanate is prepared by reacting the starting material alkyl L-phenylalanate and maleic anhydride in aqueous solution at a pH of at most 7.5. The reaction products can be isomerized with dipolar aprotic solvents into the corresponding fumaric acid monoamides and thus can be used as an intermediate in the preparation of alkyl .alpha.-L-aspartyl-L-phenylalanate.
摘要:
Resolution of the racemates of phosphorus-containing functional acetic acid derivatives can be carried out in high yield and in enantiomeric purity using hydrolases such as esterases and lipases.
摘要:
.alpha.-Glucosyl fluoride can be converted in the presence of cyclodextrin .alpha.(1.fwdarw.4)glucosyltransferase into a mixture of .alpha.- and .beta.-cyclodextrins in high yield.
摘要:
L-Phenylalanine can be prepared using microorganisms belonging to the series comprising E. coli, Paracoccus denitrificans, Torula, Rhodotorula or Streptomyces after adaptation to phenylpyruvic acid, by amination with suitable sources of nitrogen. It is advantageous to employ the microorganism in the form of fixed cells.
摘要:
Ribonucleic acid in a mixture of crude nucleic acids is selectively hydrolyzed with 5'-phosphodiesterase to 5'-ribonucleotides without hydrolyzing desoxyribonucleic acid in the mixture. Selective hydrolysis is carrying out by contacting the crude nucleic acid mixture with 5'-phosphodiesterase immobilized on a polymer carrier. The crude mixture of nucleic acids is preferably obtained by aqueous extraction of microorganisms that have previously been extracted with ammonia and a lower alcohol to remove lipids. The polymer carrier is preferably a copolymer of glycidylmethacrylate, allylglycidylether, methacrylamide and methylene-bis-methacrylamide.
摘要:
The crosslinked, porous copolymer in the form of beads and containing 50 to 99.9% by weight of recurring units of a heterocyclic 5-membered ring compound which contains a polymerizable olefinic group and which has at least one protonizable nitrogen atom in the ring, 0.1 to 50% by weight of units of a crosslinking agent, 0 to 25% by weight of units of a polymerizable organoboron or organosilicon compound and, relative to 100% by weight of the sum of the abovementioned units, 5 to 350% by weight of units of an N-vinylamide of the general formula I CH.sub.2 .dbd.CH--N(R.sup.1)--C(R.sup.2).dbd.O wherein R.sup.1 denotes hydrogen, methyl or ethyl and R.sup.2 denotes hydrogen or C.sub.1 -C.sub.3 -alkyl, or several such N-vinylamides and 0 to 40% by weight of units of another polymerizable compound or several such compounds, is prepared by inverted suspension polymerization and is used, for example, as a sorbent for acid substances from solutions thereof, preferably aqueous solutions.
摘要:
An apparatus for removing binder straps from coils of metal strip in which a cage is engageable with the coil and has a blade carriage displaceable over at least a region in which binder straps may be provided in a continuous manner so that a wedge can engage beneath the straps in succession and a cutting tool can cut through straps in a single continuous operation without interrupting the movement of the carriage. The wedge and the carriage can be provided with clamping elements to engage the strap after it is cut to allow it to be transported to a scrap bin.