0.5
orsymbol (in enzyme kinetics) for the value of the concentration of a substrate, A, in mol dm−3, at which the velocity of the reaction, v, is half the maximum velocity, V; i.e. when v = 0.5V.[...]
14
C a radioactive isotope of normal carbon (12C) emitting a weak beta particle. The half-life of 14C is 5,700 years. This radioisotope is extensively used as a tracer in molecular biology.
50
symbol for the molar concentration of an agonist that produces 50% of the maximal possible effect of that agonist. Other percentage values ([A]20, [A]40, etc.) can be specified. The action of the ...
2′-5′A
symbol for any member of a series of oligonucleotides of the general formula pa A[2′p5′A]n, where p and A are phosphoric and adenosine residues, respectively, and a and n are ...
A
symbol for1 acid‐catalysed (of a reaction mechanism).2 a residue of the α‐amino acid l‐alanine (alternative to Ala).3 a residue of the base adenine in a nucleic‐acid sequence.[...]
a
symbol for1 absorption coefficient.2 acceleration (in vector equations it is printed in bold italic (a).3 activity (def. 3).4 van der Waals coefficient.5 as subscript, denotes affinity.[...]
A
symbol for1 absorbance.2 activity (def. 2).3 affinity.4 Helmholtz function.5 mass number/nucleon number.
(A + T)/(G + C) ratio
The ratio of the sum of the adenine plus thymine bases to the sum of the guanine plus cytosine bases in a DNA molecule or preparation. The ratio is to ...
A 2 bu
orsymbol for a residue of the α, γ‐diamino acid l‐α, γ‐diaminobutyric acid, l‐2,4‐diaminobutanoic acid.
A 2 pr
orsymbol for a residue of the α,β‐diamino acid l‐α,β‐diaminopropionic acid; l‐2,3‐diaminopropanoic acid.
A* algorithm
A member of the class of best-first heuristic search techniques that attempt to find a “best” path from a given start node to a designated goal node in a problem graph. An evaluation function is used ...
A, B antigens
Mucopolysaccharides responsible for the ABO blood group system. The A and B antigens reside on the surface of erythrocytes, and differ only in the sugar attached to the penultimate monosaccharide ...
A. Penck
(1858–1945)A German mineralogist from the University of Berlin, Penck's main interest was in Quaternary glacial land-forms, which he classified according to shape. Some of his work was done in ...
