Klaus Witthohn

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There are two different pathways known to be used for the detoxification of hydrocyanic acid in insects, viz., rhodanese and β-cyano-l-ala-nine synthase. We consider the latter to be indicative for cyanogenesis, while rhodanese might, in general, play a more important role in sulfur transfer for protein synthesis. This paper reports on the distribution of(More)
Mistletoe lectin I (pML) and its isoforms ML II and III constitute the active principle in extract preparations from mistletoe, commonly used as immunomodulator in adjuvant tumour therapy. The heterodimeric disulfide-linked cytotoxic protein is classified as type II ribosome inactivating protein (RIP). Recently, the sequence coding for the mistletoe lectin(More)
An arabinogalactan-protein (AGP) from pressed juice of Echinacea purpurea herb was isolated from a high molecular weight fraction by precipitation with the beta-glucosyl Yariv reagent, followed by gel-permeation chromatography. It revealed characteristic features of other AGPs: i.e., a high amount of polysaccharide (83%) with a ratio of galactose to(More)
Extracts from the European mistletoe plant Viscumalbum have been studied for decades for their direct and indirect anticancer activity. Therefore, scientists were interested in identifying the active compound (mistletoe lectin) in these extracts and making it available as a highly purified molecule for drug development. Recombinant mistletoe lectin (INN:(More)
A method for the analysis of the rViscumin heterodimer (recombinant mistletoe lectin) based on two-dimensional (2-D) polyacrylamide gel electrophoresis and mass spectrometry was developed and used for quality control concerning purity and homogeneity of the recombinant protein processed under Good Manufacturing Practice (GMP) conditions. A series of spots(More)
The pulmonary drug delivery of proteins present an alternative to parenteral and oral administration. Nebulization of aqueous protein solutions is an ideal method for pulmonary application of therapeutic proteins considering the difficulties of their formulation as MDIs or DPIs. This research presents the effect of variable excipients on the stability of(More)
Beside the known existence of cyanoglucosides (linamarin and lotaustralin) and proteins the neurotoxin beta-cyanoalanine has been demonstrated for the first time in the defensive secretions of animals. It is proposed that beta-cyanoalanine is produced by metabolizing cyanide from the cyanoglucosides. The methanolic precipitated protein fraction contains(More)
Mistletoe lectin I (ML-I) is a type II ribosome-inactivating protein, which inhibits the protein biosynthesis at the ribosomal level. ML-I is composed of a catalytically active A-chain with rRNA N-glycosidase activity and a B-chain with carbohydrate binding specificities. Using comparative solid-phase binding assays along with electrospray ionization tandem(More)
The anticancer drug rViscumin, currently under clinical development, has been shown in previous studies to be a sialic acid specific ribosome inactivating protein (RIP). Comparative binding assays with the CD75s-specific monoclonal antibodies HB6 and J3-89 revealed rViscumin to be a CD75s-specific RIP due to identical binding characteristics toward CD75s(More)
To allow for pharmacokinetic studies in adjunction with the current clinical developments of the potent cytostatic anti-cancer drug rViscumin, a sandwich immuno-PCR (IPCR) assay was developed for the detection of rViscumin in blood plasma. The IPCR was carried out with a commercially available reagent kit, consisting of pre-assembled rViscumin-specific(More)