CRC critical reviews in biochemistry最新文献

{"title":"Signal mechanisms of phototransduction in retinal rod.","authors":"J I Korenbrot","doi":"10.3109/10409238509113605","DOIUrl":"https://doi.org/10.3109/10409238509113605","url":null,"abstract":"<p><p>The levels of intracellular molecules are modulated by illumination of rod photoreceptor cells in the vertebrate retina. Among these are Ca ions, cyclic nucleotides (cGMP in particular), and phosphate nucleotides (ATP and GTP). It is presumed now that at least two of these molecules, Ca and cGMP, may function as chemical linkers between the absorption of light by rhodopsin and the ionic channels of the plasma membrane of the rod outer segment that close when the rod is illuminated. The manuscript will review the physiology of the rod cell, the evidence in support of light-dependent changes in the intracellular levels of various small molecules, and the role of these changes in coupling rhodopsin excitation to the control of the light-sensitive membrane channels in the rod.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"17 3","pages":"223-56"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238509113605","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13721813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stereospecificity for nicotinamide nucleotides in enzymatic and chemical hydride transfer reactions.","authors":"K S You","doi":"10.3109/10409238509113625","DOIUrl":"https://doi.org/10.3109/10409238509113625","url":null,"abstract":"<p><p>The pyridine nucleotide (NAD and NADP)-linked enzymes are a large class of enzymes constituting approximately 17% of all classified enzymes. When these enzymes catalyze their reactions, the hydride transfer between the substrate and the reaction site (i.e., C-4 of the nicotinamide/dihydronicotinamide ring) of the coenzyme takes place in a stereospecific manner. Thus, in the reaction of oxidation of the reduced coenzyme, one group of enzymes catalyzes the extraction of only the hydrogen having the R configuration at the No. 4 carbon, while the other group catalyzes the removal of only that with the S configuration. Because this aspect of enzyme stereospecificity provides essential information for a given enzyme's reaction mechanism, active site structure, and evolutionary relationship with other enzymes, intensive effort has been made to establish the stereospecificities of as many enzymes as possible. This review presents the compilation of the stereospecificities of these enzymes. Some empirical rules, which are useful but not definitive, in predicting a given enzyme's stereospecificity are also described. In addition, the stereospecificity in enzymatic reactions is compared to the stereo-preference in chemical oxidoreduction of the coenzyme. In order to elucidate the mechanism for the enzyme stereospecificity, the conformations of the coenzyme in free-state and enzyme-bound state are extensively discussed here.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"17 4","pages":"313-451"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238509113625","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14288906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The hepatic asialoglycoprotein receptor.","authors":"A L Schwartz","doi":"10.3109/10409238409108716","DOIUrl":"https://doi.org/10.3109/10409238409108716","url":null,"abstract":"<p><p>Asialo- (i.e., galactose-terminal) glycoproteins are specifically and avidly recognized by a mammalian hepatic parenchymal cell receptor. This receptor, itself a glycoprotein, binds ligand molecules and directs their delivery to lysosomes for catabolism. The receptor is reutilized during this process of receptor-mediated endocytosis. Ligand specificity is conferred by galactose or N-acetyl-galactosamine at the nonreducing termini of the oligosaccharide chains. The receptor appears to be a transmembrane protein and is localized both to the cell surface as well as to several membranous intracellular compartments.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"16 3","pages":"207-33"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409108716","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17443514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Angiotensin-converting enzyme inhibitors: biochemical properties and biological actions.","authors":"M A Ondetti,&nbsp;D W Cushman","doi":"10.3109/10409238409108720","DOIUrl":"https://doi.org/10.3109/10409238409108720","url":null,"abstract":"<p><p>The review will cover the chemistry and biochemistry of angiotensin-converting enzyme inhibitors with emphasis on data published since the publication of previous reviews. The relative merits of each contribution will be evaluated, as well as their potential for leading to new discoveries. The biology of angiotensin-converting enzyme inhibitors will be brought up-to-date to give the reader an appreciation of the medical implications of this new type of antihypertensive agent.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"16 4","pages":"381-411"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409108720","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17161312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enzymology of DNA in replication in prokaryotes.","authors":"K J Marians","doi":"10.3109/10409238409113604","DOIUrl":"https://doi.org/10.3109/10409238409113604","url":null,"abstract":"<p><p>This review stresses recent developments in the in vitro study of DNA replication in prokaryotes. New insights into the enzymological mechanisms of initiation and elongation of leading and lagging strand DNA synthesis in ongoing studies are emphasized. Data from newly developed systems, such as those replicating oriC containing DNA or which are dependent on the lambda, O, and P proteins, are presented and the information compared to existing mechanisms. Evidence bearing on the coupling of DNA synthesis on both parental strands through protein-protein interactions and on the turnover of the elongation systems are analyzed. The structure of replication origins, and how their tertiary structure affects recognition and interaction with the various replication proteins is discussed.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"17 2","pages":"153-215"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409113604","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17164607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NMR studies of conformational states and dynamics of DNA.","authors":"D R Kearns","doi":"10.3109/10409238409102803","DOIUrl":"https://doi.org/10.3109/10409238409102803","url":null,"abstract":"<p><p>The application of high resolution NMR techniques to the investigation of DNA double helices in solution is currently in a rapid state of change as a result of advances in three different fields. First, new methods (cloning, enzymatic degradation, sonication, and chemical synthesis) have been developed for producing large quantities of short DNA suitable for NMR studies. Second, there have been major advances in the field of NMR in terms of the introduction of new pulse techniques and improvements in instrumentation. Finally, as a result of recent X-ray diffraction studies on short DNA helices and the discovery of left-handed Z-DNA there is heightened interest in the study of DNA structures in solution and the effect of sequence on structure. In the present review, we discuss the way in which NMR techniques have been used to probe various aspects of the DNA properties, including base pairing structure, dynamics of breathing, effect of sequence on DNA structure, internal molecular motions, the effect of environment on the DNA, and the interaction of DNA with small ligands.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"15 3","pages":"237-90"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409102803","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17265342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Translational attenuation: the regulation of bacterial resistance to the macrolide-lincosamide-streptogramin B antibiotics.","authors":"D Dubnau","doi":"10.3109/10409238409102300","DOIUrl":"https://doi.org/10.3109/10409238409102300","url":null,"abstract":"<p><p>The regulation of ermC is described in detail as an example of regulation on the level of translation. ermC specifies a ribosomal RNA methylase which confers resistance to the macrolide-lincosamide-streptogramin B group of antibiotics. Synthesis of the ermC gene product is induced by erythromycin, a macrolide antibiotic. Stimulation of methylase synthesis is mediated by binding of erythromycin to an unmethylated ribosome. The translational attenuation model, supported by sequencing data and by mutational analysis, proposes that binding of erythromycin causes stalling of a ribosome during translation of a \"leader peptide\", resulting in isomerization of the ermC transcript from an inactive to an active conformer. The ermC system is analogous to the transcriptional attenuation systems described for certain biosynthetic operons. ermC is unique in that interaction with a small molecule inducer mediates regulation on the translational level. However, it is but one example of nontranscriptional -level control of protein synthesis. Other systems are discussed in which control is also exerted through alterations of RNA conformation and an attempt is made to understand ermC in this more general context. Finally, other positive examples of translational attenuation are presented.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"16 2","pages":"103-32"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409102300","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17267882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Etheno-substituted nucleotides and coenzymes: fluorescence and biological activity.","authors":"N J Leonard","doi":"10.3109/10409238409102299","DOIUrl":"https://doi.org/10.3109/10409238409102299","url":null,"abstract":"AbstractDefinition of the individual adenine binding sites of enzymes is important for many reasons. Rendering an adenine moiety fluorescent while retaining the biological activity of the molecule of which it is a component can provide useful binding information because of the fluorescence properties. The 1,N6-ethenoadenosine phosphates and, similarly, e-modified polynucleotides, RNA, and DNA have been synthesized, and their spectroscopic properties and interactions have been studied in depth. The use of e-substituted nucleotides has helped to clarify numerous enzyme reactions, including those of ATPase and energy transfer, ATP transphosphorylase, glyceraldehyde-3-phosphate dehydrogenase, phosphofructokinase, phosphorylase b, protein kinase, pyruvate kinase, ribonucleases, RNA ligase, and others. The binding of e-substituted nucleotides or polynucleotides to proteins has been determined for F- and G-actin, heavy meromyosin, tobacco mosaic virus protein, gene 32 protein of bacteriophage T4, and chloroplast...","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"15 2","pages":"125-99"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409102299","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17424740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanistic studies of cAMP-dependent protein kinase action.","authors":"H N Bramson,&nbsp;E T Kaiser,&nbsp;A S Mildvan","doi":"10.3109/10409238409102298","DOIUrl":"https://doi.org/10.3109/10409238409102298","url":null,"abstract":"<p><p>The details of the process by which protein kinase catalyzes phosphoryl group transfers are beginning to be understood. Early work that explored the primary specificity of cAMP-dependent protein kinase action enabled the synthesis of small peptide substrates for the enzyme. Enzyme-peptide interactions seem simpler to understand than protein-protein interactions, so peptide substrates have been used in most protein kinase studies. In most investigations the kinetics for the phosphorylation of small peptides have been interpreted as being consistent with mechanisms which do not invoke phospho-enzyme intermediates (see, for example, Bolen et al.). Protein kinase has been shown to bind two metal ions in the presence of a nucleotide. Using magnetic resonance techniques the binding of these ions has been utilized to elucidate the conformation of nucleotide and peptide substrates or inhibitors when bound in the enzymic active site. Also, two new peptides with the form Leu-Arg-Arg-Ala-Ser-Y-Gly, where Y was either Pro or (N-methyl)Leu, were synthesized and found not to be substrates, within the limits of detection, for protein kinase. The striking lack of affinity that protein kinase has for such peptides which are unlikely to form a beta 3-6 turn has not been reported before. Our results may indicate that this type of turn is a requirement for protein kinase catalyzed phosphorylation or that these peptides lack the ability to form a particular hydrogen bond with the enzyme. Magnetic resonance techniques have indicated that the distance between the phosphorous in the gamma-phosphoryl group of MgATP and the hydroxyl oxygen of serine in the peptide Leu-Arg-Arg-Ala-Ser-Leu-Gly is 5.3 +/- 0.7 A. This, together with certain kinetic evidence, suggests that the mechanism by which protein kinase catalyzes phosphoryl group transfer has considerable dissociative character. Chemical modifications, including one using a peptide-based affinity label, have identified two residues at or near the active site, lysine-72 and cysteine 199. While neither of these groups has been shown to be catalytically essential, similar studies may help to identify groups that are directly involved in the catalytic process. Finally, a spectrophotometric assay for cAMP-dependent protein kinase has been described. Using this assay the preliminary results of an in-depth study of the pH dependence of protein kinase catalyzed phosphoryl group transfer have been obtained. This study shall aid in the identification of active site residues and should contribute to the elucidation of the enzyme's catalytic mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"15 2","pages":"93-124"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409102298","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17424741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural and sequence-dependent aspects of drug intercalation into nucleic acids.","authors":"S Neidle,&nbsp;Z Abraham","doi":"10.3109/10409238409110270","DOIUrl":"https://doi.org/10.3109/10409238409110270","url":null,"abstract":"<p><p>Information gained from X-ray crystallographic studies on drug-nucleic acid complexes is described, with emphasis on the intercalation process. Relevant data from NMR experiments are examined in order to highlight similarities and differences between solution and solid-state structures. Theoretical analyses of intercalation complexes are also discussed and evaluated, with respect to the structural methods, with special reference being made to nucleic acid conformation and positions of drug molecules in the binding sites.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"17 1","pages":"73-121"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238409110270","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17161315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}