The granin (chromogranin/secretogranin) family

The chromogranins/secretogranins, referred to in abbreviated form as granins, are a family of acidic secretory proteins that are found in the secretory granules of a wide variety of endocrine cells and neurons, being stored together with many different peptide hormones and neuropeptides. The recent elucidation of their primary structure has provided insights into possible functions of these proteins. Moreover, the granins have been successfully used as markers for normal and neoplastic endocrine and neuronal cells, as well as model proteins to understand the sorting mechanism involved in the formation of secretory granules.     

Approach to the analysis of diuretics and masking agents by high-performance liquid chromatography—mass spectrometry in doping control

The application of thermospray and plasmaspray high-performance liquid chromatography—mass spectrometry to the analysis of diuretics and probenecid has been investigated. The latter method gave better ionization efficiency than the former, and its response was optimized by altering the solvent composition: best results were obtained with water—methanol—acetonitrile—trifluoroacetic acid. Using different proportions of these solvents, three isocratic systems were developed to separate the compounds under study. The principal characteristic of plasmaspray positive-ion mass spectra was a protonated molecular ion and very little fragmentation was evident. In the negative ionization mode, the plasmaspray method gave mass spectra showing more fragmentation, which resulted in additional structural information. The ability of trifluoroacetic acid to form negative cluster ions precluded its use as a mobile phase component. The minimum detectable amounts determined by the analysis in the positive-ion mode was compound-dependent, but generally ca. 10–150 ng. In many cases the compounds could be detected in urine extracts.     

Asymmetric reduction of ketones with resting cells of Sulfolobus solfataricus

The method of resting cells has been of interest in the development of biocatalysts applied to organic reactions.This article deals with the use of resting cells of a thermophilic archaebacterium Sulfolobus solfataricus, in the asymmetric reduction of acyclic, cyclic, and aromatic ketones. The system allows the continuous regeneration of endogenous coenzyme with the coupled substrate approach. The results indicate that the direction of hydride attack was equatorial on the re face of the carbonyl group of substrates producing (S)-alcohols with a good optical yield. A convenient system for the reuse of resting cells has been set out to synthesize (S)-alcohols on a preparative scale.     

Archaebacterial elongation factor Tu insensitive to pulvomycin and kirromycin

A spermine-dependent, polyphenylalanine-synthesizing cell-free system having an optimum activity at 75-85 degrees C, has been developed from the extremely thermoacidophilic archaebacterium Caldariella acidophila. The C. acidophila system is totally insensitive to the EF-Tu targeted antibiotics pulvomycin (at 40 degrees C) and kirromycin (at 47-72 degrees C) contrary to control systems derived from both mesophilic (Escherichia coli) and thermoacidophilic (Bacillus acidocaldarius) eubacteria. The archaebacterial EF-Tu-equivalent factor is also immunologically unrelated to eubacterial EF-Tu and does not cross react with antibodies against Escherichia coli EF-Tu. The pulvomycin and kirromycin reactions thus provide new phyletic markers for archaebacterial ancestry.     

Structural regularities in tetraether lipids of Caldariella and their biosynthetic and phyletic implications

Individual di(biphytanyl) diglycerol tetraether lipids from thermoacidophile archaebacteria of the Caldariella series, with differently cyclized biphytanyl components, are separated and shown to have structures 8–12, with the glycerol and biphytanyl components demonstrably both antiparallel and with partial assignments of stereochemistry. Tetraethers with alternative arrangements of the components are absent. The structures allow previous observations on these and related lipids to be rationalized both biosynthetically and phyletically.     

The ATP/2e ratio during photosynthesis in intact spinach chloroplasts.

Addition of ribose-5-phosphate to intact spinach chloroplasts in the absence of added P_i resulted in a conversion of part of the Benson-Calvin cycle into a linear sequence so that triose phosphate accumulated during CO₂ fixation stoichiometrically with the O₂ evolved (triose phosphate / O₂ ratio was 2.0). The fortunate consequence of this effect is that the $\text{ATP}\text{2e}$ ratio may be calculated from the 3-phosphoglycerate and triose phosphate accumulated and the O₂ evolved. In this way the $\text{ATP}\text{2e}$ ratio was shown to be 2.0, with cyclic or pseudocyclic phosphorylation contributing less than 9% to the total phosphorylation.     

Photocross-linking analysis of the contact surface of tRNA Met in complexes with Escherichia coli methionine:tRNA ligase.

Photoinduced covalent cross-linking has been used to identify a common surface of four methionine-accepting tRNAs which interact specifically with the Escherichia coli methionine:tRNA ligase (EC 6.1.1.10). tRNA--ligase mixtures were irradiated, and the covalently linked complexes were isolated and digested with T1 RNase (Schimmel & Budzik, 1977). The fragments lost from the elution profile of the T1 RNase digest were considered to have been cross-linked to the protein and therefore in intimate contact with the enzyme. Only specific cognate tRNA--ligase pairs produce covalently linked complexes. The four substrate tRNAs used in this study have substantially different sequences, but all showed a common cross-linking pattern, supporting the view that the sites cross-linked to the enzyme reflect the functionally common contact surface rather than particularly photoreactivity regions of tRNA. The cross-linked contact surface is comprised of three regions: (1) the narrow groove of the anticodon stem and its extension into the anticodon loop; (2) the 3' terminal residues; and (3) the 3' side of the "T arm". Unlike previous studies with other tRNAs, the D arm is not involved and significant radiation damage is suffered by the tRNA which must be taken into account in the analysis. The results are consistent with and complement chemical modification studies [Schulman, L. H., & Pelka, H. (1977) Biochemistry 16, 4256].     

Hemoglobin J Cairo: beta 65 (E9) Lys leads to Gln, A new hemoglobin variant discovered in an Egyptian family.

The present report describes clinical, hematological and biochemical studies of a 27-year old Egyptian woman in whom a fast moving Hb variant was found. The abnormal Hb constituted 48% of the total erythrocyte Hb of the propositus and her father. Structural studies demonstrated that in the abnormal Hb lysine beta 65 is replaced by glutamine. The new Hb mutant is designated hemoglobin J Cairo beta 65 (E9) Lys leads to Gln. This substitution results in only a moderate decrease in cooperativity. No evidence of Hb instability was found. A slight anemic state has been observed in the propositus since she reached adolescence.