results in expression of the modified human haptocorrin protein identified by seq id no 3 according to this embodiment the 21 nucleotide sequence for the zinc binding u201c rdadadr u201d sequence is inserted between nucleotides 423 and 424 of human haptocorrin according to one embodiment to test the expression of modified haptocorrin sequence 1 ynhczn the modified gene e g seq id no 1 was expressed in insect cells the cell extract containing the modified haptocorrin was loaded onto a b 12 column and then eluted shown in fig3 the eluent was then tested for the presence of haptocorrin using a haptocorrin primary antibody and positive results see fig4 indicated that the insect cell expressed modified haptocorrin sequence 1 ynhczn is indeed expressed and that the modified protein is capable of binding b 12 as described herein and in accordance with an embodiment the human haptocorrin protein encoded by the tcn1 gene can be modified to include one or more zinc binding sites another embodiment of a modified tcn1 gene containing a zinc binding site sequence is seq id no 4 which contains the zinc binding site sequence mtsttlvkcacepclcnvdpskaidrnglyycseacadghtggskgcghtgcnchg seq id no 5 which is a smta metallothionein sequence metallothioneins are small cysteine rich proteins that are extremely good at binding metal ions for example the smta gene from synechococcus binds zinc ions extremely well according.