The oxygen-respiratory pigment equilibrium of the hemocyanin and myoglobin of the amphineuran mollusccryptochiton stelleri

✍ Scribed by Manwell, Clyde

• Publisher: Wiley (John Wiley & Sons)
• Year: 1958
• Tongue: English
• Weight: 585 KB
• Volume: 52
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030520210

✦ Synopsis

There are two systems in which respiratory pigments appear to be specialized for the purpose of increasing the efficiency of the diffusive transfer of oxygen from one biological phase to another : (1) the transfer of oxygen from the hemoglobin of the blood to the hemoglobin of the muscles -myoglobin (Millikan, '39) ; and, (2) the transfer of oxygen across the placenta from maternal to fetal hemoglobin (Barcroft, '47 ; Lamport, '54). Studies have indicated that in both of these cases the oxygen dissociation curve of the "acceptor respiratory pigment" (myoglobin or fetal hemoglobin) lies to the left of that f o r the corresponding "donor respiratory pigment," i.e., the oxygen affinity of the "acceptor pigment" is greater than that of the "donor pigment." The greater this difference in the oxygen dissociation curves, the larger the amount of oxygen per unit time that will diffuse across the barrier separating the two respiratory pigments. This increased efficiency results from the ability of the "acceptor respiratory pigment " to become appreciably saturated with oxygen at low tensions of that gas. Consequently, oxygen tension on the acceptor side of the barrier remains low, thereby increasing the magnitude of the oxygen gradient, and, thus, the net diffusive transfer of dissolved oxygen.