(a.) Capable of neutralizing four molecules of a monacid base; having four hydrogen atoms capable of replacement by bases; quadribasic; -- said of certain acids; thus, normal silicic acid, Si(OH)4, is a tetrabasic acid.
Example Sentences:
(1) The precursor also has potential sites for glycosylation, integrin binding (RGD), and a tetrabasic amino acid (RKKR) site for potential cleavage of the precursor peptide to a biologically active protein.
(2) Adrenocorticotropin (ACTH) is cleaved at the tetrabasic residue site, in pituitary intermediate lobe secretory vesicles, to yield ACTH1-17 and corticotropin-like intermediate lobe peptide (CLIP).
(3) The ATP-induced effects were inhibited in a dose-dependent manner by Mg2+ and greatly potentiated in its absence, which suggests that the tetrabasic ATP4 is probably the active species and that a phosphotransferase activity is not involved in its effects.
(4) Following removal of the signal peptide, a rapid cleavage at the tetrabasic sequence Arg-Arg-Lys-Arg separates the amino and carboxyl regions of the prohormone.
(5) Extracellular conversion of the 71-kDa peptide to the 68-kDa peptide involved cleavage at the sequence Arg-Lys-Lys-Arg (amino acids 106-109), since deletion of this tetrabasic sequence resulted in secretion of the 71-kDa peptide without further conversion to the 68-kDa form.
(6) A point mutation in the human insulin receptor gene in a patient with type A insulin resistance alters the amino acid sequence within the tetrabasic processing site of the proreceptor molecule from Arg-Lys-Arg-Arg to Arg-Lys-Arg-Ser.
(7) We have studied the specificity requirements for processing of the human insulin proreceptor by successively replacing each basic amino acid in the tetrabasic cleavage site with alanine.
(8) ATP (as the tetrabasic acid, ATP4-) applied externally to rat mast cells causes the formation of lesions which permit influx and efflux of low molecular weight, normally impermeant aqueous solutes.
(9) A well-conserved tetrabasic residue has been shown to be the first endoproteolytic cleavage site of the precursor, giving rise to two intermediates, which are differentially processed and packaged.
(10) Also unique to this new TGF beta is an insertion of two amino acids near the N-terminus of the processed peptide which would result in a 114 amino acid mature protein after cleavage from the precursor at a tetrabasic arg-arg-arg-arg site.
(11) Each of these equine H7 haemagglutinins possess a tetrabasic amino acid cleavage site separating the HA1 and HA2 domains but, in addition, all ten contain a nine amino acid insertion prior to the tetrabasic sequence.
(12) Bovine intermediate lobe secretory vesicle membranes were screened for proteolytic enzyme activity that will cleave the tetrabasic residues of ACTH.
(13) The acidic, ACTH-converting enzyme cleaved ACTH1-39 at the tetrabasic residues between the Arg17-Arg18 bond to yield ACTH1-17 and CLIP, but did not cleave paired basic residues of pro-opiomelanocortin.
(14) This enzyme activity was characterized as a Ca(2+)-activated serine protease with unique specificity for the tetrabasic residues of ACTH1-39.
(15) The pH optimum, distinct specificity for tetrabasic residues, and subcellular localization of the acidic ACTH-converting enzyme indicate a function of this enzyme in the in vivo conversion of ACTH1-39 to alpha-melanocyte-stimulating hormone in intermediate lobe secretory vesicles which have an acidic internal pH.
(16) In solutions containing Mg2+ and Ca2+, ATP is in equilibrium between the tetrabasic form (ATP4-) and its bidentate coordination complexes, i.e., MgATP2- and CaATP2-.
Univalent
Definition:
(a.) Having a valence of one; capable of combining with, or of being substituted for, one atom of hydrogen; monovalent; -- said of certain atoms and radicals.
Example Sentences:
(1) Experiments indicated that complement deposition altered functionally bivalent IgG3 antibody in the immune complex into a univalent one.
(2) Equilibrium measurements of interactions of anti-DNP antibodies, prepared using DNP-PLL and several DNP-proteins for immunization, with DNP(0.6)-PLL(240) and with the univalent hapten, epsilon-DNP-L-lysine, were made utilizing the technique of fluorescence quenching.
(3) Explicit expressions are derived which describe the binding of a univalent ligand to equivalent and independent sites on each state of an acceptor undergoing indefinite self-association that is governed by an isodesmic equilibrium constant KI.
(4) A computer model was constructed which can generate all of the common univalent behaviours.
(5) In these male cells there was no decrease of chiasmata or increase of autosomal univalents with age, and there were some interstrain differences.
(6) Two homogeneous univalent hapten-protein conjugates, prepared by the covalent attachment of a single 2,4-dinitrophenyl (DNP-) or 2,4,6-trinitrophenyl (TNP-) side chain to the cysteine-SH in the active site of the enzyme papain, have been found to exhibit large Cotton effects in the wavelength region of the absorption bands of the DNP or TNP groups.
(7) Equivalent concentrations of binding sites of the bivalent F(ab)2 and univalent Fab fragments of anti-CEA were identical to the immunoglobulin G fraction in the standard inhibition curve.
(8) At a hydrophobic surface, molecules move apart and local water becomes strongly bonded, inert, and viscous and accumulates large cations, univalent anions, and compatible solutes.
(9) Of particular interest in that regard is the observation that the traditional logit-log analyses yield linear plots with the predicted slope of unity even though antigen univalence is an implicit assumption in their application.
(10) (3) The two stable states of the nerve membrane, which are readily demonstrable in TEA-treated or internally perfused squid giant axons, are shown to represent bivalent cation-rich and univalent cation-rich states of the nerve membrane.
(11) Only benzaldehyde dehydrogenase I is activated by K(+) and certain other univalent cations.
(12) Male meiosis in Mesostoma ehrenbergii ehrenbergii (2x = 10) is characterized by extreme restriction of chiasma formation; 3 pairs of chromosomes form bivalents at metaphase I which are associated by single very distally localized chiasma, while two pairs of chromosomes remain as unpaired univalents.
(13) Human red blood cells (RBCs) that are deficient in an integral membrane-associated protein ("stomatin") of apparent molecular mass 31 Kd show a catastrophic increase in passive membrane permeability to the univalent cations Na+ and K+ and are stomatocytic in shape.
(14) We demonstrate that shifts of the conductance-voltage (g-V) characteristic of PG films produced by changes of univalent or divalent cation concentrations result from changes of the membrane surface potential on one or both sides.
(15) The electrical resistances and rates of self-exchange of univalent critical ions across several types of collodion matrix membranes of high ionic selectivity were studied over a wide range of conditions.
(16) The steady-state solutions (Kirchhoff-Hill theorem) yield expressions for the relationship between the small signal conductance of univalent ions and the concentration of these ions in the external bathing medium (a saturation curve) and for the ionic currents and the steady-state current-voltage curve (N-shaped).
(17) The incidence of oocytes with univalents in the slides made by Tarkowski's method was much higher than in those made by ours in both age and strain groups (P less than 0.05-0.001).
(18) Our findings support the assumption that the altered activity of the Na-K-ATPase (modified by the presence of Ca-2+) is responsible for the univalent cation activation of the CaATPase.
(19) Under the conditions used univalent cations (Na(+),K(+) and Li(+)) inhibited the binding.
(20) The k-absorption edge spectrum of LyCuLP was consistent with the coordination of univalent copper.