What's the difference between molecule and substituent?

Molecule


Definition:

  • (n.) One of the very small invisible particles of which all matter is supposed to consist.
  • (n.) The smallest part of any substance which possesses the characteristic properties and qualities of that substance, and which can exist alone in a free state.
  • (n.) A group of atoms so united and combined by chemical affinity that they form a complete, integrated whole, being the smallest portion of any particular compound that can exist in a free state; as, a molecule of water consists of two atoms of hydrogen and one of oxygen. Cf. Atom.

Example Sentences:

  • (1) A series of human cDNA clones of various sizes and relative localizations to the mRNA molecule were isolated by using the human p53-H14 (2.35-kilobase) cDNA probe which we previously cloned.
  • (2) Glucocorticoids have numerous effects some of which are permissive; steroids are thus important not only for what they do, but also for what they permit or enable other hormones and signal molecules to do.
  • (3) The results demonstrated that K2PtCl4 was bound to a greater degree than CDDP in this system with 3-5 and 1-2 platinum atoms respectively, bound per transferrin molecule.
  • (4) Complementarity determining regions (CDR) are conserved to different extents, with the first CDR region in all family members being among the most conserved segments of the molecule.
  • (5) Even with hepatic lipase, phospholipid hydrolysis could not deplete VLDL and IDL of sufficient phospholipid molecules to account for the loss of surface phospholipid that accompanies triacylglycerol hydrolysis and decreasing core volume as LDL is formed (or for conversion of HDL2 to HDL3).
  • (6) However, the presence of these two molecules was restored if testosterone was supplemented immediately after orchiectomy.
  • (7) In the second approach, attachment sites of DTPA groups were directed away from the active region of the molecule by having fragment E1,2 bound in complex, with its active sites protected during the derivatization.
  • (8) PMNs could be primed for PMA-triggered oxidative burst by muramyl peptide molecules (MDP) and two of its adjuvant active nonpyrogenic derivatives.
  • (9) These same molecules may be equally responsible for the pathologic characteristics of the immune response seen, for example, in inflammatory bowel diseases.
  • (10) A cDNA library prepared from human placenta has been screened for sequences coding for factor XIIIa, the enzymatically active subunit of the factor XIII complex that stabilizes blood clots through crosslinking of fibrin molecules.
  • (11) T cell costimulation by molecules on the antigen presenting cell (APC) is required for optimal T cell proliferation.
  • (12) The lipid A moiety was shown to be responsible for this novel biological activity of the LPS molecule.
  • (13) Both systems indicated that the Kupffer cell modified endotoxin by enriching the lipid content of the molecule and shortening the length of the O-antigen.
  • (14) Photoreactions induced in that proper sensitizer molecules absorb UV-light or visible light.
  • (15) At 100 microM-ACh the apparent open time became shorter probably due to channel blockade by ACh molecules.
  • (16) Flow cytofluorometric analysis of the strain distribution of the molecules defined by the mAb revealed that two of the antibodies (I-22 and III-5) were directed against nonpolymorphic determinants of Thy-1, whereas V-8 mAb reacted only with Thy-1.2+ lymphocytes.
  • (17) At a fixed concentration of nucleotide the effectiveness of elution was proportional to the charge on the eluting molecule.
  • (18) The relative rates of reduction of several spin-labeled molecules that partition differently across the hy-drophobic-interface of inner membranes from rat liver mitochondria were investigated.
  • (19) The seve polypeptide chains investigated had generalyy similar properties; all contained two residues per molecule of tryptophan and N-acetylserine was the common N-terminal amino acid residue.
  • (20) Much information has accumulated on the isolation and characterization of a heterogeneous group of molecules that inhibit one or more of the bioactivities of interleukin 1.

Substituent


Definition:

  • (n.) Any atom, group, or radical substituted for another, or entering a molecule in place of some other part which is removed.

Example Sentences:

  • (1) Replacement of vinyl groups with bulkier substituents (hydroxyethyl or acetyl groups) decreases holoenzyme stability and catalytic activity.
  • (2) The molar refractivity has been shown to be a superior parameter for the description of the activity of sulphonamides than the sum of electronegativities of atoms making up a heterocyclic substituent in the sulphonamide molecule and molecular weight of the substituent.
  • (3) Energy conformational calculations on these compounds were also carried out using the empirical energy program called MOLMEC, in order to better understand how the 4-R substituents modulate receptor binding affinities and efficacies.
  • (4) The N-substituents included methyl, benzyl, and beta-hydroxy- and beta-chloroethyl groups.
  • (5) Substitution at the 5'-position resulted in decreased efficacy as inhibitors of uridine kinase, particularly if the substituent was large.
  • (6) Enzyme-inhibiting ability for individual alkylphenols can be estimated based on the quantitative structure-activity relationship developed by Dewhirst (1980) and is a function of the free hydroxyl group, electron-donating ring substituents, and hydrophobic aromatic ring substituents.
  • (7) All other broad-spectrum benzimidazole anthelmintics, regardless of substituent at the 2 position (methyl carbamate or thiazolyl group), are flat.
  • (8) Difference spectra for the tetracyclines were dependent on the characteristics of the ring substituents.
  • (9) Activity was insensitive to oxygen and CO if the substrates had no additional substituents on either ring or contained only electron-donating substituents.
  • (10) The hypothesis that opiate agonism requires an N substituent in the axial position does not appear to be consistent with the increased potency of beta isomers in which axial N substituents are thermodynamically more unstable.
  • (11) The ability of the monocarboxylate analogues to inhibit depends strongly on the nature of substituents, particularly at the second carbon.
  • (12) The receptor subregion that interacts with the propyl C-1 of 1 is more tolerant of bulk and of polar substituents than the subregion that interacts with propyl C-3.
  • (13) The relative reactivities of three o-substituted phenols can be explained in terms of steric hindrance which is minimal for a single o-substituent.
  • (14) Sucrose esters were prominent surface constituents and 3-methylvaleric acid, 2- and 3-methylbutyric acid, and methylpropionic acid accounted for 60%, 25% and 9%, respectively, of total C3--C7 acyl substituents.
  • (15) In compounds with other substituents that promote activity, C-6 alpha substitution with -CH3, -Cl, or -Br strongly enhances activity; -F, -OCH3, carbonyl, or the unsubstituted compound promotes weak binding; and -OC2H5, -OAc, -OCOOCH3, or -OH eliminates binding activity.
  • (16) The hypoprothrombinemia in vitamin K-deficient female rats was caused by beta-lactam antibiotics with N-methyltetrazolethiol, thiadiazolethiol and methyl-thiadiazolethiol as the 3'-position substituent of the cephem nucleus.
  • (17) After prolonged adaptation of strain BN6 to growth on 6A2NS, this organism readily converted all naphthalene-2-sulfonates with OH- or NH2-substituents in the 5-, 6-, 7-, or 8-position.
  • (18) Six new 5(1H)oxo-2,3-dihydroimidazo[1,2-a]pyrimidine-6-carboxylic ethyl esters bearing an aromatic substituent in position 1 or 2 were obtained.
  • (19) This radioligand was selected as a synthetic target because of its potency as a 5HT3-receptor antagonist, its selectivity for this receptor viz a viz other 5HT-receptor subtypes, and the ability to readily incorporate three tritia via the indazole N-CH3 substituent.
  • (20) Instead, the latter experiment yielded 1,5-anhydro-2,3-di-O-methyl-D-mannitol, establishing the presence in the polysaccharide of terminal (nonreducing) D-mannopyranosyl groups bearing 4,6-O-(1-carboxyethylidene) substituents.

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