Trace Element Speciation in Food
↳ [54] Iron and Zinc Compounds in the Muscle Meats of Beef, Lamb, Pork and Chicken

"Figure 1 shows that the soluble zinc in all meats is distributed between five main components.

The first zinc peak corresponds to the exclusion volume of the column (molecular weight approximately 130 000) and therefore represents high molecular weight zinc. The zinc in this peak is possibly associated with a-macroglobulin which has a molecular weight of 820 000 and is known to account for one-third of all plasma zinc.[30]

Zinc peak II eluted in the same volume as the reference protein, transferrin, at a molecular weight of 76 000. Transferrin is known to bind a small amount of plasma zinc.[30]

The third zinc peak is very large and eluted at a molecular weight of approximately 65 000. Some, if not all, of the zinc in this peak is probably bound to albumin (molecular weight 67 000). Albumin is one of the sarcoplasmic proteins of meat[31] and is the predominant form of zinc in plasma.[30]

Zinc peak IV is also large and eluted at a molecular weight of approximately 35 000. This peak probably consists of the zinc metallo-enzyme carbonic anhydrase which has the same molecular weight, is a major soluble form of zinc in liver,[32] and accounts for nearly all the zinc found in erythrocytes.[30]

The fifth zinc peak eluted in a volume corresponding to low molecular weight compounds (< 12 000). The fractions from zinc peak Vb reacted with ninhydrin which suggests that this peak consists of zinc bound to amino acids.[19] Fractions from peak Va showed no reaction with ninhydrin and therefore probably consist of zinc bound to small peptides."

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