Hostname: page-component-848d4c4894-4hhp2 Total loading time: 0 Render date: 2024-06-04T23:53:05.942Z Has data issue: false hasContentIssue false

NADP-linked dehydrogenases in secreted milk

Published online by Cambridge University Press:  01 June 2009

Murray R. Grigor
Affiliation:
Department of Biochemistry, University of Western Australia, Nedlands, Western Australia 6009
Peter E. Hartmann
Affiliation:
Department of Biochemistry, University of Western Australia, Nedlands, Western Australia 6009

Summary

The activities of glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase, malic enzyme, lactate dehydrogenase and malate dehydrogenase have been determined in secreted milk from sows, rats and rabbits. Within each species, although there was considerable variation in the absolute activities of these enzymes, the relative activities were similar to those observed for, or previously published for mammary homogenates. The only exception was milk glucose 6-phosphate dehydrogenase which tended to lose activity upon prolonged storage in the mammary gland. These results suggest that the pattern of milk enzymes can be an accurate reflection of that occurring in the mammary gland.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1985

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Baldwin, R. L. & Milligan, L. P. 1966 Enzymatic changes associated with the initiation and maintenance of lactation in the rat. Journal of Biological Chemistry 241 20582066CrossRefGoogle ScholarPubMed
BauMan, D. E., Brown, R. E. & Davis, C. L. 1970 Pathways of fatty acid synthesis and reducing equivalent generation in mammary gland of rat, sow, and cow. Archives of Biochemistry and Biophysics 140 237244CrossRefGoogle ScholarPubMed
Calvert, D. T. & Knight, C. H. 1983 Rate of milk secretion during the long suckling interval in the rabbit. Journal of Physiology 334 65P66PGoogle Scholar
Cowie, A. T. 1969 Variations in the yield and composition of the milk during lactation in the rabbit and the galactopoietic effect of prolactin. Journal of Endocrinology 44 437450CrossRefGoogle ScholarPubMed
Grigor, M. R. 1983 Malic enzyme from the rat mammary gland. Biochemistry International 6 751755Google ScholarPubMed
Grigor, M. R. 1984 Multiple molecular forms of rat mammary glucose 6-phosphate dehydrogenase: proposed role in turnover of the enzyme. Archives of Biochemistry and Biophysics 229 612622CrossRefGoogle ScholarPubMed
Grigor, M. R., Geursen, A., Sneyd, M. J. & Warren, S. M. 1982 Regulation of lipogenic capacity in lactating rats. Biochemical Journal 208 611618CrossRefGoogle ScholarPubMed
Gul, B. & Dils, R. 1969 Enzymic changes in rabbit and rat mammary gland during the lactation cycle. Biochemical Journal 112 293301CrossRefGoogle ScholarPubMed
Gumaa, K. A., Greenbaum, A. L. & McLean, P. 1973 Adaptive changes in satellite systems related to lipogenesis in rat and sheep mammary gland and in adipose tissue. European Journal of Biochemistry 34 188198CrossRefGoogle ScholarPubMed
Helmbrhorst, E. & Stokes, G. B. 1980 Microcentrifuge desalting: a rapid, quantitative method for desalting small amounts of protein. Analytical Biochemistry 104 130135CrossRefGoogle Scholar
Jenness, R. 1974 The composition of milk. In Lactation, a Comprehensive Treatise, vol. 3, pp. 3107 (eds Larson, B. L. and Smith, V. R.). New York: Academic PressGoogle Scholar
Kjellberg, B. & Karlsson, B. W. 1967 Comparative analyses of lactic and malic dehydrogenases and their multiple molecular forms in milk from various animal species and man. Comparative Biochemistry and Physiology 22 397413CrossRefGoogle ScholarPubMed
Richards, A. H. & Hilf, R. 1972 Influence of pregnancy, lactation and involution on glucose-6-phosphate dehydrogenase and lactate dehydrogenase isoenzymes in the rat mammary gland. Endocrinology 91 287295CrossRefGoogle ScholarPubMed
Shahani, K. M., Kwan, A. J. & Friend, B. A. 1980 Role and significance of enzymes in human milk. American Journal of Clinical Nutrition 33 18611868CrossRefGoogle ScholarPubMed