synthesis of anabolic precursors for
amino-acid synthesis.
amphiphilicDescribing a molecule
that has both hydrophilic and hy-
drophobic parts, as in *detergents.
amphiprotic See amphoteric; sol-
vent.
ampholyteA substance that can
act as either an acid, in the presence
of a strong base, or a base, when in
the presence of a strong acid.
ampholyte ionSee zwitterion.
amphotericDescribing a com-
pound that can act as both an acid
and a base (in the traditional sense of
the term). For instance, aluminium
hydroxide is amphoteric: as a base
Al(OH) 3 it reacts with acids to form
aluminium salts; as an acid H 3 AlO 3 it
reacts with alkalis to give alumi-
nates. Oxides of metals are typically
basic and oxides of nonmetals tend
to be acidic. The existence of ampho-
teric oxides is sometimes regarded as
evidence that an element is a metal-
loid. Compounds such as the amino
acids, which contain both acidic and
basic groups in their molecules, can
also be described as amphoteric. Sol-
vents, such as water, that can both
donate and accept protons are usu-
ally described as amphiprotic (see sol-
vent).
AMTSee alphamethyltryptamine.
a.m.u. See atomic mass unit.
amylase Any of a group of closely
related enzymes that degrade starch,
glycogen, and other polysaccharides.
Plants contain both α- and β-
amylases; the name diastaseis given
to the component of malt containing
β-amylase, important in the brewing
industry. Animals possess only α-
amylases, found in pancreatic juice
(as pancreatic amylase) and also (in
humans and some other species) in
saliva (as salivary amylase or ptyalin).
Amylases cleave the long polysaccha-
ride chains, producing a mixture of
glucose and maltose.amyl group Formerly, any of sev-
eral isomeric groups with the for-
mula C 5 H 11 –.amylopectinA *polysaccharide
comprising highly branched chains
of glucose molecules. It is one of the
constituents (the other being amy-
lose) of *starch.amyloseA *polysaccharide consist-
ing of linear chains of between 100
and 1000 linked glucose molecules.
Amylose is a constituent of *starch.
In water, amylose reacts with iodine
to give a characteristic blue colour.anabolic steroids Steroid hor-
mones related to the male sex hor-
mone testosterone. They promote
the development of masculine char-
acteristics and increase muscle
growth. Anabolic steroids have been
used medically for various conditions
but are also used illegally by sports-
men and women and by body-
builders. They have a number of
deleterious side effects and are a con-
trolled drug in the UK and many
other countries. Their use is banned
by nearly all major sports regulating
bodies. They can be detected in blood
and urine by gas chromatography–
mass spectroscopy.anabolismThe metabolic synthesis
of proteins, fats, and other con-
stituents of living organisms from
molecules or simple precursors. This
process requires energy in the form
of ATP. Drugs that promote such
metabolic activity are described as
anabolic. See metabolism. Compare ca-
tabolism.Analar reagent A chemical
reagent of high purity with known35 Analar reagent
a