Dictionary of Chemistry [6th Ed.]

mustard gas See sulphur

mustard; nitrogen mustard.

mutarotation Change of optical

activity with time as a result of spon-

taneous chemical reaction.

myoglobinA globular protein oc-

curring widely in muscle tissue as an

oxygen carrier. It comprises a single

polypeptide chain and a *haem

group, which reversibly binds a mol-

ecule of oxygen. This is only relin-

quished at relatively low external

oxygen concentrations, e.g. during

strenuous exercise when muscle oxy-

gen demand outpaces supply from

the blood. Myoglobin thus acts as an

emergency oxygen store.

myristic acidSee tetradecanoic

acid.

mustard gas 364

m