"ZT[1,1]={"blabla", 0, n+13, 4*g1*g2/3 + g2^2};"

ZT[1,1]={"blabla", 0, n+13, 4*g1*g2/3 + g2^2};

"ZT[1,1]={"blabla", 0, n+13 , 4*g1*g2/3 +  g2^2}"

PutAppend[StringJoin["ZT[",ToString[i],",",ToString[k],"]=" ,"{", ToString[Last[ReadList[StringJoin["!some command ","'",ToString[Z[i,k][[1]]],"'"],String]]] ,"}"], StringJoin["some_table_up_",ToString[somenumber],"_babam.m"]]

{"blabla", 0, n+13 , 4*g1*g2/3 + g2^2}