Biochemi

Mycobacterium phlei (strain Timothy) (Mycobacterium smegmatis ATCC 19249) is characterized by the presence of a family of alkali-labile glycolipids, reminiscent of the trehalose-containing lipooligosaccharide class of antigens but lacking the nonreducing trehalose core. Through a combination of methylation analyses, 1H and 13C NMR, two-dimensional 1H/1H and 1H/13C NMR, fast atom bombardment-mass spectrometry, gas chromatography-mass spectrometry, and other analytical techniques, these new structures were shown to possess three distinct features...

RecA protein can bind to double-stranded DNA even without the cofactor ATP if a DNA intercalator such as ethidium bromide is present (Thresher R. J., and Griffith, J. D. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 5056-5060). We have studied the structure and association kinetics of the ethidium-promoted DNA-RecA complex in order to understand the role of this intercalator in the DNA-RecA association process, information that could provide insight about the binding mechanism of RecA to DNA. Both linear dichroism and fluorescence measurements show that ethidium remains intercalated between the DNA bases in the RecA-DNA complex in the absence of ATP...

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Rat platelet lysate contained appreciable phospholipase A2 activity. In agreement with literature data this enzymatic activity eluted in the void volume of a Sephadex G-100 column. When the void volume peak was chromatographed over a Matrex gel blue A column, part of the phospholipase A2 activity ran through, whereas the remainder was bound to the gel. The latter activity could be eluted with buffers containing a high salt concentration. In contrast, phospholipase A2 activity solubilized from rat platelet lysates by treatment with high salt eluted from Sephadex G-100 columns with an apparent molecular weight of 10-15 kDa...

Removal of the ocular lens in adult newts (Notophthalmus viridescens) is followed by a series of cellular events leading to regeneration of a new lens by cell type conversion of pigmented iris epithelial cells at the dorsal pupillary margin (Yamada, Curr. Top. Dev. Biol. 2:247-283, 1967). Following depigmentation and five to seven cell divisions, iris epithelial cells redifferentiate into lens fiber cells and synthesize crystallin proteins (Yamada, Curr. Top. Dev. Biol. 2:247-283, 1967). This process is dependent upon neural retina in vivo (Stone, Anat...

The VASI gene encoding the valyl-tRNA synthetase from yeast was isolated and sequenced. The gene-derived amino acid sequence of yeast valyl-tRNA synthetase was found to be 23% homologous to the Escherichia coli isoleucyl-tRNA synthetase. This is the highest level of homology reported so far between two distinct aminoacyl-tRNA synthetases and is indicative of an evolutionary relationship between these two molecules. Within these homologous sequences, two functional regions could be recognized: the HIGH region which forms part of the binding site of ATP and the KMSKS region which is recognized as the consensus sequence for the binding of the 3'-end of tRNA (Hountondji, C...

We established three lymphoblastoid cell lines from a bullous pemphigoid (BP) patient's peripheral blood by means of EBV transformation, which produced human monoclonal anti-basement membrane zone (BMZ) IgG antibodies. A blocking immunofluorescence test using these MAbs, designated 5A, 5E, and 10D, revealed that 5A and 5E recognized the same or a closely associated epitope, but the epitope for 10D was completely different, 18 of 30 BP sera blocked the reactivity of 10D MAb and 17 sera blocked 5E, while 9 sera did not block the staining of either antibody...

We describe the molecular identification of a gene, designated T1, whose expression in mouse NIH 3T3 cells is strongly induced by the Ha-ras(EJ) and v-mos oncogenes and by serum. The T1 gene encodes a 38.5-kDa protein, as predicted from its primary sequence and shown by in vitro translation. The protein was processed at its amino terminus and extensively modified by N-linked glycosylation in vitro in the presence of microsomal vesicles. Sequence comparison of T1 with the MIPSX data base (Max-Planck-Institut für Biochemie, Martinsried/Munich) revealed similarity to the human carcinoembryonic antigen, a tumor marker which is overexpressed in colon adenocarcinomas and in fetal tissues...

The controlled clinical trial reported here is part of a multicenter clinical and basic research project, sponsored by the German Federal Minister of Science and Technology, directed by a standing commission of the president of the Max-Planck-Gesellschaft, and coordinated by the Max-Planck-Institut für Biochemie, München. Overall, 249 patients with rheumatoid arthritis (RA) were enrolled by 16 participating hospitals. In addition to NSAID treatment, patients were randomly given either interferon gamma (IFN-gamma) or placebo...

Glutamate aspartate transaminase (EC 2.6.1.1) is a dimeric enzyme with identical subunits with each active site containing pyridoxal 5'-phosphate linked via an internal Shiff's base to a lysine residue. It is not known if these sites interact during catalysis but negative cooperativity has been reported for binding of the coenzyme (Arrio-Dupont, M. (1972), Eur. J. Biochem. 30, 307). Also nonequivalence of its subunits in binding 8-anilinonaphthalene-1-sulfonate (Harris, H.E., and Bayley, P. M. (1975), Biochem...

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The problem of the presence of enzymes in retina rod outer segments is summarized using both literature and the author's own data. Difficulties in the solving of this problem are analyzed. It has been shown that some enzymes involved in the primary mechanisms of the photoreceptor process are localized in the inner segment of the photoreceptor cell at a distance from the photoreceptor membranes. A conclusion is drawn that the enzymes necessary for rhodopsin (or its retinal-part) conversions as well as those ensuring synthesis and decay of cyclic nucleotides are concentrated in the outer segments...

The regulation of protein synthesis in heart muscle has been investigated by many authors under both normal and pathological conditions. This review summarizes the evidence for the dependence of normal heart protein synthesis from normal serum levels of insulin, amino acids, fatty acids and glucose. A decreased serum concentration of these substances causes an inhibition of heart muscle protein synthesis by 30--60%. Various drugs and other chemical lead to similar impairments of heat muscle protein synthesis...