CRC critical reviews in biochemistry最新文献

{"title":"Positional isotope exchange.","authors":"F M Raushel,&nbsp;J J Villafranca","doi":"10.3109/10409238809103118","DOIUrl":"https://doi.org/10.3109/10409238809103118","url":null,"abstract":"<p><p>The detection of intermediates in enzyme-catalyzed reactions can be accomplished by several techniques. For those intermediates which do not have easily observed electronic spectra, use can be made of isotope exchange phenomena if the chemistry of the reaction is appropriate. Recently, the technique of positional isotope exchange (intramolecular isotopic scrambling) has been used to study several reactions which have been thought to involve high-energy intermediates in their mechanisms. A review of some of these reactions and the limitations of the method are presented in this article.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"23 1","pages":"1-26"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238809103118","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14413656","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":"DNA strand exchanges.","authors":"J. Griffith, L. Harris","doi":"10.3109/10409238809083375","DOIUrl":"https://doi.org/10.3109/10409238809083375","url":null,"abstract":"Biochemical and electron microscopic studies of the strand exchange reactions catalyzed by the RecA protein of Escherichia coli and the UvsX protein of T4 phage reveal that these reactions proceed in three distinct steps. The first step, termed joining, involves the assembly of RecA (or UvsX) protein onto a single-stranded DNA (ssDNA) molecule and the subsequent search for homology with a double-stranded DNA (dsDNA) partner and formation of a stable synapsis. In the second step (envelopment/exchange), the exchange of DNA strands occurs fueled by the hydrolysis of ATP. The third step (release of products) entails the resolution of the complexes and dissociation of the protein from the DNAs. The structure of the intermediates in the in vitro reactions catalyzed by the RecA and UvsX proteins is emphasized in this review. The results of pairing different DNA molecules in vitro (such as linear ssDNA pairing with linear or supertwisted dsDNA) are described. Paranemic joints represent a major pathway of joining between two DNA molecules which may involve, in some cases, most of the DNA substrate molecules. Since the nature of paranemic joints has only recently begun to be understood, the nature, role, and possible in vivo function of paranemic joining are considered.","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"23 Suppl 1 1","pages":"S43-86"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238809083375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69419464","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 cAMP cascade in the nervous system: molecular sites of action and possible relevance to neuronal plasticity.","authors":"Y Dudai","doi":"10.3109/10409238709101484","DOIUrl":"https://doi.org/10.3109/10409238709101484","url":null,"abstract":"<p><p>Many intercellular messages regulate the activity of their target cells by altering the intracellular level of cAMP and, as a consequence, the phosphorylation state of proteins which serve as substrates for cAMP-dependent protein kinase. Such regulation plays a crucial role in neuronal development, neuronal function, and neuronal plasticity (e.g., elementary learning mechanisms). Ample information has been accumulated in recent years on the enzymes that regulate the level of cAMP or respond to it, on the regulation of cAMP synthesis by neurohormones, neurotransmitters, ions, and toxins, on neuronal-specific substrate proteins that are phosphorylated by the cAMP-dependent kinase, and on the interaction of the cAMP-cascade with other second-messenger systems within neurons. Such data, obtained by a combination of molecular-biological, biochemical, and cellular approaches, shed light on the detailed mechanisms by which modulation of a ubiquitous molecular cascade leads to a great variety of short-term as well as long-term specific neuronal responses and alterations.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"22 3","pages":"221-81"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238709101484","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13592695","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":"Lipid-protein interactions and the function of the Ca2+-ATPase of sarcoplasmic reticulum.","authors":"C Hidalgo","doi":"10.3109/10409238609113615","DOIUrl":"https://doi.org/10.3109/10409238609113615","url":null,"abstract":"<p><p>Regardless of the nature of the protein constituents of membranes, the molecular arrangement of lipids interacting with them must satisfy hydrophobic, ionic, and steric requirements. Biological membranes have a great diversity of lipid constituents, and this diversity might have functional roles. It has been proposed, for example, that the hydrophobic regions of membrane proteins are stabilized in the membrane through interactions with lipids able to adopt configurations other than the bilayer structure. Progress in understanding at the molecular level how lipid-protein interactions control the properties of membrane proteins has been hindered by the lack of information concerning the structure of the hydrophobic regions of membrane proteins. Nevertheless, there are many examples in the literature describing how changes in the lipid environment affect physical and biochemical properties of membrane proteins. From these studies, discussed in this review, an overall picture of how lipids and proteins interact in membranes is beginning to emerge.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"21 4","pages":"319-47"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238609113615","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14093108","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":"Liver alcohol dehydrogenase.","authors":"G. Pettersson","doi":"10.3109/10409238609113616","DOIUrl":"https://doi.org/10.3109/10409238609113616","url":null,"abstract":"The article deals with the structure and function of liver alcohol dehydrogenase and reviews mainly literature published after 1979, i.e., summarizes progress made in the field since Klinman presented her review on alcohol dehydrogenases. The emphasis will be on high-resolution crystallographic data, results obtained with metal-substituted enzyme derivatives, and on the mechanism and pH dependence of the catalytic reaction.","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"21 4 1","pages":"349-89"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238609113616","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69419456","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 use of Xenopus oocytes for the study of ion channels.","authors":"N Dascal","doi":"10.3109/10409238709086960","DOIUrl":"https://doi.org/10.3109/10409238709086960","url":null,"abstract":"<p><p>Recently, in addition to the \"traditional\" research on meiotic reinitiation and fertilization mechanisms, the oocytes of the African frog Xenopus laevis have been exploited for the study of numerous aspects of ion channel function and regulation, such as the properties of several endogenous voltage-dependent channels and the involvement of second messengers in mediation of neurotransmitter-evoked membrane responses. In addition, injection of these cells with exogenous messenger RNA results in production and functional expression of foreign membranal proteins, including various voltage- and neurotransmitter-operated ion channels originating from brain, heart, and other excitable tissues. This method provides unique opportunities for the study of the structure, function, and regulation of these channels. A multidisciplinary approach is required, involving molecular biology, electrophysiology, biochemistry, pharmacology, and cytology.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"22 4","pages":"317-87"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238709086960","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13595486","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":"Liver alcohol dehydrogenase.","authors":"G Pettersson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The article deals with the structure and function of liver alcohol dehydrogenase and reviews mainly literature published after 1979, i.e., summarizes progress made in the field since Klinman presented her review on alcohol dehydrogenases. The emphasis will be on high-resolution crystallographic data, results obtained with metal-substituted enzyme derivatives, and on the mechanism and pH dependence of the catalytic reaction.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"21 4","pages":"349-89"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14432153","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":"Molecular and cellular aspects of nerve regeneration.","authors":"M Schwartz","doi":"10.3109/10409238709083737","DOIUrl":"https://doi.org/10.3109/10409238709083737","url":null,"abstract":"<p><p>Injury of an axon leads to at least four independent events, summarized in Figure 1: first, deprivation of the nerve cell body from target-derived or mediated substances, which leads to a derepressed or a permissive state; second, disruption of anterograde transport, with a resultant accumulation of anterogradely transported molecules; third, environmental response with possible consequent changes in constituents of the extracellular matrix and substances secreted from the surrounding cells; and fourth, appearance of growth inhibitors and modified protease activity. It seems that the first three of these events are obligatory, but not sufficient, i.e., they lead to a growth state only if the cell body is able to respond to the injury-induced signals from the environment (a and b). The regenerative state is characterized by alterations in protein synthesis and axonal transport and by sprouting activity. The subsequent elongation of the growing fibers depends on a continuous supply of appropriate growth factors. These factors are presumably anchored to the appropriate extracellular matrix that serves as a substratum for elongating fibers. It should be mentioned that the proliferating nonneuronal cells have a conducive effect on regeneration by forming a scaffold for the growing fibers. Accordingly, the lack of regeneration may stem from a deficiency in the ability of glial cells to provide the appropriate soluble components or from insufficient formation of extracellular matrix. In this respect, one may consider regeneration of an injured axon as a process which involves regeneration of both the nonneuronal cells and the supported axons. The regeneration of glial cells may fulfill the rules which are applied to regeneration of any other proliferating tissue. Furthermore, the processes of regeneration in the axon and the glial cells are mutually dependent. Perhaps the triggering factors provided by the nonneuronal cells affect the nonneuronal cells themselves by modulating their postlesion gliosis and thereby inducing their appropriate activation. In such a case, regeneration of nonneuronal cells may resemble an autocrine type of regulation that exists also during ontogeny. The growth regulation is shifted back to the paracrine type upon neuronal maturation or cessation of axonal growth. When the elongating fibers reach the vicinity of the target organ, they are under the influence of the target-derived factors, which guide the fibers and eventually cease their elongation.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"22 2","pages":"89-110"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238709083737","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13592694","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":"Aspects of the structure, function, and applications of superoxide dismutase.","authors":"J V Bannister,&nbsp;W H Bannister,&nbsp;G Rotilio","doi":"10.3109/10409238709083738","DOIUrl":"https://doi.org/10.3109/10409238709083738","url":null,"abstract":"<p><p>The current status of superoxide dismutase (SOD) is that it is an enzyme with diverse ramifications. This review attempts an understanding of SOD as a structural, functional, and biological entity. Accordingly, the review is in three parts. The first part discusses SOD in terms of protein structure, proceeding from primary to secondary and three-dimensional structure for the three forms of SOD: copper/zinc SOD, manganese SOD, and iron SOD. This is the order of structural knowledge of the enzyme. Iron SOD is an enzyme of prokaryotes and some higher plants. Manganese SOD is an enzyme of prokaryotes and eukaryotes. Copper/zinc SOD is an enzyme of eukaryotes and certain prokaryotes. The evolutionary relationships of the three forms of SOD, the status of the copper/zinc SOD gene in prokaryotes, and the cloning and sequencing of SOD genes are discussed. The second part of the review deals with the catalytic mechanism of SOD in the three forms of the enzyme. Structural and mechanistic conclusions from various spectroscopic studies are critically considered. A detailed picture is given of the active site of copper/zinc SOD. The third part is a review of SOD in the general context of oxygen toxicity. After consideration of the question of superoxide toxicity and superoxide pathology, several areas in which SOD has been investigated or used as a tool in a biochemical, pharmacological, or clinical context are discussed, including population genetics; trisomy 21; development and senescence; the nutritional copper, zinc, and manganese status; hemolysis and anemia; oxygen toxicity in the lung and nervous system; inflammation, autoimmune disease and chromosome breakage, ischemia and degenerative changes; radiation damage; and malignancy. A comprehensive picture is given of measurements of SOD activity in disease states, and the question of superoxide-related disease is considered at several points.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"22 2","pages":"111-80"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238709083738","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14442826","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":"Mechanism and stereoelectronic effects in the lysozyme reaction.","authors":"A J Kirby","doi":"10.3109/10409238709086959","DOIUrl":"https://doi.org/10.3109/10409238709086959","url":null,"abstract":"<p><p>Lysozyme occupies a special place in the history of enzymology as the first enzyme to have its three-dimensional crystal structure elucidated by Phillips and co-workers in 1965. The crystallography, and much biochemical work, revealed three factors likely to be important for the mechanism of action: catalysis by the carboxyl group of Glu-35, catalysis by the ionized carboxyl group of Asp-52, and the conformation of the bound polysaccharide substrate. The work of the last 20 years has defined likely roles for the catalytic groups, but discussion of the conformational question came to a head only very recently with the suggestion that the fundamental stereoelectronic requirements of the glycoside-cleavage reaction might be decisive. Recent work on all three interlinked factors are reviewed.</p>","PeriodicalId":75744,"journal":{"name":"CRC critical reviews in biochemistry","volume":"22 4","pages":"283-315"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/10409238709086959","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14453321","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}