The influence of halogen substituents on the course of hydrogallation and hydroalumination reactions.

Treatment of trimethylsilylethynylbenzene derivatives with HGaCl(2) afforded products, [C(6)H(6-x){C(H)=C(SiMe(3))GaCl(2)}(x)], in which by a very fast cis/trans-rearrangement the Ga and H atoms occupied opposite sides of the resulting C=C double bonds. The stability of the cis-forms considerably increased upon application of 1,3-dibromo- and pentafluorophenylalkyne derivatives. Two pairs of cis/trans-isomers could be characterized by crystal structure determinations and allow the direct comparison of structural parameters.

Purification, cloning and characterization of a novel peroxidase isozyme from sweetpotatoes (Ipomoea batatas).

An anionic peroxidase from sweetpotato tubers is purified and characterized. The isozyme ibPrx15 is purified to homogeneity by affinity chromatography using a concanavalin A column. The isoelectric point was determined to pI 4.

The reactions of dialkylgallium hydrides with tert-butylethynylbenzenes--a systematic investigation into the course of hydrogallation reactions.

The reactions of bis- and tris(tert-butylethynyl)benzenes with dialkylgallium hydrides afforded two different types of products. 1,4-Di(tert-butylethynyl)benzene and dialkylgallium hydrides R(2)GaH bearing relatively small substituents (R = Et, nPr) gave the expected addition products with each C triple bond C triple bond inserted into a Ga-H bond. The intact GaR(2) groups are attached to those carbon atoms which are in alpha-position to the benzene rings, and intermolecular Ga-C interactions led to the formation of one-dimensional coordination polymers.

Crystal structures of recombinant human purple Acid phosphatase with and without an inhibitory conformation of the repression loop.

The crystal structure of human purple acid phosphatase recombinantly expressed in Escherichia coli (rHPAP(Ec)) and Pichia pastoris (rHPAP(Pp)) has been determined in two different crystal forms, both at 2.2A resolution. In both cases, the enzyme crystallized in its oxidized (inactive) state, in which both Fe atoms in the dinuclear active site are Fe(III).