Abstract: A compound which has the biological action of inducing cell differentiation has general chemical formula (I), in which R.sub.1 is a straight or branched chain or cyclic alkyl or alkenyl group; R.sub.2 is an alkoxy or hydroxy group; R.sub.3 is a hydrogen or halogen atom; and, R.sub.4 is a halogen atom. Preferred values for the groups are R.sub.1 =C.sub.3 to C.sub.8 alkyl; R.sub.2 =methoxy; and, either or both of R.sub.3 and R.sub.4 =chlorine. The compounds: 1) 2,6-dihydroxy-3,5-dichloro-4-methoxy valerophenone; 2) 2,6-dihydroxy-3,5-dichloro-4-methoxy butyrophenone; and, 3) 2,6-dihydroxy-3-chloro-4-methoxy valerophenone are of particular interest.

Abstract: Methods are provided for determining the presence or absence of ragged ends in polymeric proteins or protein products, by means of fast atom bombardment and high mass mass spectrometry (preferably high field magnet mass spectrometry). The methods may be modified for locating N- or C-terminal peptide in a polymeric protein or protein product and for assigning disulphide bridges in polymeric protein or protein products. The methods are applicable to other biopolymers such as nucleotides and carbohydrates.