Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acetyl CoA carboxylase catalyzes the first committed step in the biosynthesis of long chain fatty acids. In Escherichia coli, the enzyme consists of three subunits that are isolated separately and display distinct functional properties. Here we report the crystallization and preliminary X-ray analysis of one of these components, namely biotin carboxylase. The crystals are grown by microdialysis against 10 mM potassium phosphate (pH 7.0), 1 mM EDTA, 2 mM DTT and 1 mM NaN3 at 4 degrees C. They belong to the space group P2(1)2(1)2(1) with unit cell dimensions of a = 61.9 A, b = 96.1 A and c = 180.6 A and contain one dimer per asymmetric unit. The crystals diffract to a nominal resolution of 2.2 A. From a mechanistic standpoint, biotin carboxylase is especially interesting in that it is the smallest protein within its class and is one of only two carboxylases that can utilize free biotin as a substrate.
J Mol Biol 1994 Jan 07
PMID:Preliminary X-ray crystallographic analysis of biotin carboxylase isolated from Escherichia coli. 790 51

A method for objective quantification of hamster sperm movement parameters as an indicator of maturation along the epididymis was established using a computerised system. Analysis of spermatozoa released into medium from five epididymal regions showed that the most drastic increases in percentage motility and curvilinear velocity (VCL) occurred from the distal corpus to the beginning of the proximal cauda and in straight-line velocity (VSL) from the beginning to a more distal site within the proximal cauda region. Both high osmolarity (400 mOsm/kg) and the thiol-oxidising agent diamide (10 microM) increased flagellar straightness of distal corpus spermatozoa, but VSL was increased only with the latter. The thiol-reducing agent dithiothreitol (DTT, 1mM) stimulated and maintained percentage motility and velocities of spermatozoa from the caput, stimulated only percentage motility of distal corpus sperm, but decreased velocities of those from the proximal cauda in prolonged incubation. In rats, diamide increased path straightness but not velocities of caput spermatozoa and yet caused immotility within 15 min, whereas DTT prolonged the maintenance of in vitro motility. The slight increases in kinematic parameters in the presence of DTT were enhanced by a 2-min preincubation with diamide. The finding that the effects of DTT and diamide were not compensatory suggests that the influence of the SH/S-S status on sperm movement is multifaceted, with decreasing sensitivity to stimulation upon sperm maturation.
Mol Reprod Dev 1994 Jul
PMID:Maturation of hamster epididymal sperm motility and influence of the thiol status of hamster and rat spermatozoa on their motility patterns. 791 86

The regulatory role of Ca(2+)-stimulated adenosine 5'-triphosphatase (Ca(2+)-ATPase) in Ca2+ transport system of rat liver nuclei was investigated. Ca2+ uptake and release were determined with a Ca2+ electrode. Ca(2+)-ATPase activity was calculated by subtracting Mg(2+)-ATPase activity from (Ca(2+)-Mg2+)-ATPase activity. The release of Ca2+ from the Ca(2+)-loaded nuclei was evoked progressively after Ca2+ uptake with 1.0 mM ATP addition, while it was only slightly in the case of 2.0 mM ATP addition, indicating that the consumption of ATP causes a leak of Ca2+ from the Ca(2+)-loaded nuclei. The presence of N-ethylmaleimide (NEM; 0.1 mM) caused an inhibition of nuclear Ca2+ uptake and induced a promotion of Ca2+ release from the Ca(2+)-loaded nuclei. NEM (0.1 and 0.2 mM) markedly inhibited nuclear Ca(2+)-ATPase activity. This inhibition was completely blocked by the presence of dithiothreitol (DTT; 0.1 and 0.5 mM). Also, DTT inhibited the effect of NEM (0.1 mM) on nuclear Ca2+ uptake and release. Meanwhile, verapamil and diltiazem (10 microM), a blocker of Ca2+ channels, did not prevent the NAD+ (1.0 and 2.0 mM), zinc sulfate (1.0 and 2.5 microM) and arachidonic acid (10 microM)-induced increase in nuclear Ca2+ release, suggesting that Ca2+ channels do not involve on Ca2+ release from the nuclei. These results indicates that an inhibition of nuclear Ca(2+)-ATPase activity causes the decrease in nuclear Ca2+ uptake and the release of Ca2+ from the Ca(2+)-loaded nuclei. The present finding suggests that Ca(2+)-ATPase plays a critical role in the regulatory mechanism of Ca2+ uptake and release in rat liver nuclei.
Mol Cell Biochem 1994 Feb 23
PMID:Involvement of Ca(2+)-stimulated adenosine 5'-triphosphatase in the Ca2+ releasing mechanism of rat liver nuclei. 803 82

The sarcoplasmic reticulum (SR) membranes isolated from rabbit heart were preincubated at pH 6.8 or 7.8 and their Ca2+ pump properties were compared at pH 6.8. The ATP-dependent azide insensitive oxalate-stimulated Ca2+ uptake was reduced more rapidly from the membranes preincubated at 37 degrees C at pH 7.8 than from those preincubated at pH 6.8. The Ca(2+)-Mg(2+)-ATPase, and the Ca(2+)-dependent formation of 110 kDa acylphosphate were also inhibited by the preincubation at the higher pH. Including 1 mM DTT in the preincubation medium reduced the inactivation. The preincubation at 37 degrees C in the presence or absence of DTT caused membranes to become more leaky as the loss of Ca2+ uptake was more rapid than that of ATPase or the acylphosphate formation. The loss of these activities was not accompanied by a breakdown of the protein as monitored in Western blots. It is hypothesized that the SR Ca2+ pump inactivation involves a key-SH group and that the lower pH provides a compensatory protective mechanism for the SR during acidosis.
Mol Cell Biochem 1993 Sep 08
PMID:Effect of pH on stability of sarcoplasmic reticulum calcium pump in rabbit heart. 810 93

alpha 1-Proteinase inhibitor (alpha 1-PI) is the major endogenous inhibitor of human leukocyte elastase (HLE). We have employed two different methods to quantitate the binding of alpha 1-PI to extracellular matrix (ECM), composed of 51% glycoproteins and proteoglycans, 37% types I and III collagen, and 12% elastin, derived from rat heart smooth muscle cells. alpha 1-PI is tightly bound to ECM via a saturable adsorption process; the bound protein fails to dissociate from the matrix after repeated washing. Binding of alpha 1-PI is unaffected by the prior removal of ECM glycoproteins with trypsin. Binding to ECM is not decreased in the presence of high salt but is decreased at low pH. A 40-fold excess of unlabeled alpha 1-PI displaces only 50% of [125I]alpha 1-PI prebound to ECM. A 30% decrease in the levels of alpha 1-PI bound to ECM is observed after DTT washes of ECM preincubated with alpha 1-PI or when alpha 1-PI is modified with iodoacetamide prior to incubation with ECM, implying that a fraction of bound alpha 1-PI is covalently linked to ECM via disulfide bond formation. Moreover, high molecular weight complexes between [125I]alpha 1-PI and ECM components can be visualized by SDS-PAGE under nonreducing conditions but disappear upon reduction. Approximately 50% of the total alpha 1-PI bound covalently or noncovalently to ECM retains the ability to inhibit HLE-mediated ECM proteolysis. alpha 1-PI-HLE complexes bound to ECM can be visualized by SDS-PAGE following the addition of HLE to ECM that was pretreated with [125I]alpha 1-PI. alpha 1-PI from normal plasma or serum also binds to ECM with retention of immunoreactivity and partial retention of inhibitory activity. However, ECM pretreated with alpha 1-PI-deficient serum retains no HLE-inhibitory activity.
Am J Respir Cell Mol Biol 1993 Dec
PMID:Human alpha 1-proteinase inhibitor binds to extracellular matrix in vitro. 825 98

Ca2+ dependent conformational change of collagenase resistant fragment (CRF) of human surfactant protein A (SP-A) was studied by measurements of the far UV circular dichroism spectrum. The spectrum was altered by Ca2+ and DTT. The beta-sheet content was decreased by the addition of Ca2+ from 28.1 to 26.6%. On the other hand, the beta-sheet content was increased in the presence of dithiothreitol from 28.1 to 36.0%, and decreased by the addition of Ca2+ from 36.0 to 30.5%. The total Ca2+ concentration required for half maximal change of the ellipticity at 220 nm was estimated to be 30 microM both in the presence and absence of dithiothreitol. One of the functions of SP-A, enhancement of phospholipid uptake by alveolar type II cells, was abolished by the addition of 2-mercaptoethanol. These results strongly indicate a relationship between the conformation of CRF and SP-A functions.
Biochem Mol Biol Int 1993 Jun
PMID:Calcium and dithiothreitol dependent conformational changes in beta-sheet structure of collagenase resistant fragment of human surfactant protein A. 836 13

The study addressed to understand whether or not lipoproteins at low concentrations could modulate Receptor-'C' dependent platelet signalling revealed that LDL, like exogenous cholesterol, had the capacity to initiate PLD-dependent platelet signalling in a dose dependent fashion and this effect was inhibited in presence of HDL; cAMP; DTT; Zn++ and butanol whereas cGMP had no effect upon this PLD-dependent signalling. Further Receptor 'C' from platelet in the purified-form displayed LDL-or cholesterol-dependent autophosphorylation at the tyrosine residues and this Receptor-'C' tyrosine kinase (Receptor-Ck) activity contributed to the observed LDL-or cholesterol -dependent PLD activity in human platelets. Based upon these results coupled with earlier results, an attempt was made to define the lipoprotein-dependent platelet signalling pathway.
Mol Cell Biochem 1995 Oct 18
PMID:Lipoprotein receptor 'CK'--dependent signalling in human platelets. 856 63

Complete activation of chloroplast fructose-1, 6-bisphosphatase by dithiothreitol involves the reduction of its four disulfide bonds as revealed by thiol titration and activity measurement. Both before and after reduction, the enzyme is inhibited by the thiol-specific reagent 5,5'-dithiobis(2-nitro-benzoic acid) with complete inactivation upon modifications of the four accessible thiols. However, oxidative modification of the enzyme facillitates the reduction of the four mentioned disulfide bonds as the process of activation by DTT is accelerated.
Biochem Mol Biol Int 1996 Aug
PMID:Redox modifications of spinach chloroplast fructose-1, 6-bisphosphatase. 886 11

We have isolated the F0F1-ATP synthase complex from oligomycin-sensitive mitochondria of the green alga Chlamydomonas reinhardtii. A pure and active ATP synthase was obtained by means of sonication, extraction with dodecyl maltoside and ion exchange and gel permeation chromatography in the presence of glycerol, DTT, ATP and PMSF [corrected]. The enzyme consists of 14 subunits as judged by SDS-PAGE. A cDNA clone encoding the ATP synthase alpha subunit has been sequenced. The deduced protein sequence contains a presequence of 45 amino acids which is not present in the mature protein. The mature protein is 58-70% identical to corresponding mitochondrial proteins from other organisms. In contrast to the ATP synthase beta subunit from C. reinhardtii (Franzen and Falk, Plant Mol Biol 19 (1992) 771-780), the protein does not have a C-terminal extension. However, the N-terminal domain of the mature protein is 15-18 residues longer than in ATP synthase alpha subunits from other organisms. Southern blot analysis indicates that the protein is encoded by a single-copy gene.
Plant Mol Biol 1996 Sep
PMID:Isolation and characterization of the mitochondrial ATP synthase from Chlamydomonas reinhardtii. cDNA sequence and deduced protein sequence of the alpha subunit. 891 27

The non-A beta component (NAC) of Alzheimer's disease amyloid is a newly discovered 35 amino acid peptide found to be closely linked to the beta-amyloid fibrils in senile plaques. Apolipoprotein E (apoE) is another prominent constituent of senile plaques. In vitro studies have shown that apoE binds beta-amyloid (A beta) with high avidity, but it is unknown to what extent apoE interacts with NAC. We examined the interactions between apoE and NAC and found that apoE bound synthetic NAC, forming a complex that resisted reducing agents and separation on SDS-PAGE. The complex could be formed using apoE from either purified human very low density lipoprotein (VLDL) particles, unfractionated human cerebrospinal fluid (CSF), or recombinant protein. The binding was established within 15 min upon mixing, and the interaction between NAC and apoE was dose-dependent and specific as revealed by competition experiments. The NAC-apoE complex was affected by non-physiological pH, but not by reducing agents such as DTT or beta-mercaptoethanol. ApoE exists in different isoforms of which the apoE3 genotype is the most frequent. Notably, the apoE4 genotype has been linked to late-onset Alzheimer's disease. This study presents evidence that apoE3 as well as apoE4 bind NAC, but the binding to apoE4 is about twice as strong as to apoE3. The isoform-specific binding of NAC to apoE may thus play an important role in amyloidogenesis and in the sequestering of apoE in senile plaques during the progress of Alzheimer's disease.
Brain Res Mol Brain Res 1997 Feb
PMID:Isoform-specific binding of human apolipoprotein E to the non-amyloid beta component of Alzheimer's disease amyloid. 903 Jul 4


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