Protein derivative containing grafted ultraviolet-absorbing radicals, the process for its preparation and composition in which it is present

Claim 1

A chemically modified protein derivative which has a molecular weight of about 500 to 50,000 and which corresponds to the following general formula: ##STR16## in which formula: Y is a radical of a molecule--capable of absorbing ultraviolet radiation; P 1 and P 2 are independently chain protein units which are not acylated or chemically modified by nucleophilic addition or substitution; N + (R 2 ) 4 , in M + represents H + , a cation derived from an alkali metal or from half an atom of magnesium, or N + (R 2 ) 4 , in which formula the radicals R 2 are identical or different and represent a hydrogen atom or an alkyl or hydroxyalkyl radical having at most 4 carbon atoms; each Q is independently an alkyl, aryl or aralkyl radical of a constituent aminoacid of the protein; T represents O, NH or, if the protein contains one or more cysteine units, S; Z is: (i) a radical SO 3 --M + , the cation M + being as defined; or (ii) SR 3 , in which formula R 3 represents: ##STR17## in which formulae p is 0 or an integer from 1 to 5, R 4 is a hydrogen atom or an alkyl radical having at most 4 carbon atoms and R 5 represents: ##STR18## in which formulae D is a linear or branched alkylene group containing a total of from 2 to 10 carbon atoms, the cation M.sup.⊕ is as defined above, the radicals R 6 being identical or different and representing a hydrogen atom or an alkyl or hydroxyalkyl radical having at most 4 carbon atoms, and E.sup.⊖ being a halide ion or RCOO.sup.⊖, RSO 3 .sup.⊖ or RSO 4 .sup.⊖, R representing a hydrocarbon rest containing from 1 to 10 carbon atoms; or alternatively (iii) an amino radical originating from a basic aminoacid of the protein, monosubstituted or disubstituted by a radical R 3 ; q is an integer from 1 to 5, with the proviso that, if Z represents a radical SO 3 .sup.⊖ M.sup.⊕ or SR 3 , q is necessarily equal to 1 and the protein contains cystine units;