Relevance of glycine and cysteine residues as well as N- and C-terminals for the activity of protein histidine phosphatase.

There is increasing evidence that reversible phosphorylation of histidine residues regulates numerous important cellular processes. The first protein histidine phosphatase (PHP) from vertebrates was discovered just recently. Here, we report on amino acids and domains essential for activity of PHP.

Phosphorylation of the growth factors bFGF, NGF and BDNF: a prerequisite for their biological activity.

The aim of this work was to test whether growth factors such as basic fibroblast growth factor (bFGF), nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) undergo autophosphorylation and whether this affects their biological activity. Incubation of those growth factors with [gamma-(32)P]ATP resulted in phosphorylation in vitro. The phosphate bond was resistant to alkaline pH, yet acid-labile.

ATP-citrate lyase as a substrate of protein histidine phosphatase in vertebrates.

The first protein histidine phosphatase from vertebrates discovered recently was found in a variety of tissues, however, a physiological substrate protein was missing. Phosphorylation of liver extracts in the presence of EDTA, followed by SDS-PAGE and autoradiography showed labeling of three proteins. Acid- and alkaline-treatment revealed the existence of N-phosphates.

Expression and one-step purification of a fully active polyhistidine-tagged cytochrome bc1 complex from Rhodobacter sphaeroides.

The fbcB and fbcC genes encoding cytochromes b and c1 of the bc1 complex were extended with a segment to encode a polyhistidine tag linked to their C-terminal sequence allowing a one-step affinity purification of the complex. Constructions were made in vitro in a pUC-derived background using PCR amplification. The modified fbc operons were transferred to a pRK derivative plasmid, and this was used to transform the fbc- strain of Rhodobacter sphaeroides, BC17.

Substituted 4-acylpyrazoles and 4-acylpyrazolones: synthesis and multidrug resistance-modulating activity.

A series of 4-acyl-3-pyrazolone derivatives with a 3-substituted 2-hydroxy-3-aminopropyl chain attached to pyrazole N-1 (7-20) as well as isomeric 4-acyl-5-(3-substituted 3-amino-2-hydroxypropoxy)pyrazole derivatives (5, 6) were synthesized, and their multidrug resistance (MDR)-modulating activity was measured using the daunomycin efflux assay. Reaction of N1-substituted 4-acyl-3-pyrazolones (tautomer to 4-acyl-5-hydroxypyrazoles) with excessive epichlorohydrin and successive treatment with an appropriate amine resulted in N-alkylation and thus afforded the target pyrazolone derivatives 7-20. In contrast, O-alkylation occurred upon reaction with 1 equiv of epichlorohydrin and subsequent treatment with amine leading to the corresponding 4-acyl-5-pyrazolyl ethers 5 and 6.