Peptide-metal ion pharmaceutical preparation and method

A method of preparing a diagnostic pharmaceutical and performing a diagnostic procedure in a patient, comprising the steps of:

• a) preparing a diagnostic pharmaceutical comprising a peptide comprising a biological-function domain and a metal ion-binding domain, wherein the metal ion-binding domain comprises amino acids available for binding selected from the group consisting of cysteine, histidine, penicillamine, deacylated methionine, lysine, arginine, aspartic acid, glutamic acid, tyrosine and mixtures thereof, and a positively-charged transition metal, wherein complexes comprising the positively-charged transition metal and amino acids selected from the group consisting of cysteine, histidine, penicillamine, deacylated methionine, lysine, arginine, aspartic acid, glutamic acid, tyrosine and mixtures thereof, are formed, and wherein the peptide is selected from the group consisting of
• (R.sub.1)-[Y.sub.1 ].sub.n -(R.sub.2),
• (R.sub.1)-[Y.sub.1 -(R.sub.2)-Y.sub.1 ].sub.n -(R.sub.3)
• and (R.sub.1)-[Y.sub.1 -(R.sub.2)-Y.sub.2 ].sub.n -(R.sub.3)
• and wherein the medically useful metal ion-binding domain is unrelated to metallothionein, requires no initial reduction of disulfide bonds, and is selected from one of the group consisting of [Y.sub.1 ].sub.n, [Y.sub.1 -(R.sub.2)-Y.sub.1 ].sub.n and [Y.sub.1 -(R.sub.2)-Y.sub.2 ].sub.n in which n is a number between 1 and about 6 and Y.sub.1 and Y.sub.2 are amino acids comprising a sulfur, nitrogen or oxygen which is available for binding to mental ions, or can be made available for binding to metal ions, selected from the group consisting of cysteine, histidine, penicillamine, deacylated methionine, lysine, arginine, aspartic acid, glutamic acid, tyrosine and mixtures thereof;
• the biological-function domain comprises at least one of the group consisting of R.sub.1, R.sub.2, and R.sub.3 and further comprises an amino acid sequence containing from 1 to about 20 amino acids;
• and those portions of R.sub.1, R.sub.2, and R.sub.3 not comprising the biological-function domain each comprise an amino acid sequence containing from 0 to about 20 amino acids;
• b) labeling the pharmaceutical with a medically useful metal ion, wherein the medically useful metal ion displaces the positively-charged transition metal, wherein complexes comprising the medically useful metal ion and metal ion-binding domain comprising amino acids selected from the group consisting of cycteine, histidine, penicillamine, deacylated methionine, lysine, arginine, aspartic acid, glutamic acid, tyrosine and mixtures thereof, are formed;
• c) administering to a patient the medically useful metal ion-labeled peptide in an amount effective for imaging;
• and
• d) imaging by metal ion detection means.