Fluorometric determination of isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP + dependent) in ruminant milk

Torben Larsen; R  Rupp; N C Friggens; J A A Pires

doi:10.1016/j.animal.2022.100593

Fluorometric determination of isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP ⁺ dependent) in ruminant milk

Torben Larsen^*, R Rupp, N C Friggens, J A A Pires

^*Corresponding author for this work

Department of Animal and Veterinary Sciences - ANIVET Ruminant Nutrition (RUN)

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

Abstract

The enzyme isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP+ dependent) located in the mammary cell cytosol mediates the synthesis of the majority of reducing equivalents for the energetically demanding milk fat and cholesterol synthesis in mammary cell cytosol. The present article presents a novel fluorometric method for quantification of the activity of this enzyme (IDH) in ruminant milk without pretreatment of the sample. Further, 493 goat milk samples – harvested before, during and after a nutritional restriction – were analysed for IDH activity i) with addition of extra substrate (isocitrate), and ii) with the intrinsic isocitrate solely. The IDH activity ranged from 0.22 to 15.4 units [nano moles product/(ml * min)] (un-supplemented) and from 0.22 to 45.6 units (isocitrate supplemented). The IDH activity increased considerably in milk during the nutritional restriction period concomitant with the increase in the metabolite isocitrate concentration and somatic cell count and returned to the initial level shortly after restriction period. The present ‘high through-put’ analytical method may be beneficial in future studies to phenotype modifications in mammary energy metabolism and milk fat synthesis, for which IDH activity may be a biomarker.

Original language	English
Article number	100593
Journal	Animal
Volume	16
Issue	8
Number of pages	11
ISSN	1751-7311
DOIs	https://doi.org/10.1016/j.animal.2022.100593
Publication status	Published - Aug 2022

Keywords

Goat
Isocitrate
Isocitrate dehydrogenase-1
Lipogenesis
Milk enzyme

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10.1016/j.animal.2022.100593Licence: CC BY-NC-ND

Cite this

@article{2f37aaa7c8944405affee944534c56f2,

title = "Fluorometric determination of isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP + dependent) in ruminant milk",

abstract = "The enzyme isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP+ dependent) located in the mammary cell cytosol mediates the synthesis of the majority of reducing equivalents for the energetically demanding milk fat and cholesterol synthesis in mammary cell cytosol. The present article presents a novel fluorometric method for quantification of the activity of this enzyme (IDH) in ruminant milk without pretreatment of the sample. Further, 493 goat milk samples – harvested before, during and after a nutritional restriction – were analysed for IDH activity i) with addition of extra substrate (isocitrate), and ii) with the intrinsic isocitrate solely. The IDH activity ranged from 0.22 to 15.4 units [nano moles product/(ml * min)] (un-supplemented) and from 0.22 to 45.6 units (isocitrate supplemented). The IDH activity increased considerably in milk during the nutritional restriction period concomitant with the increase in the metabolite isocitrate concentration and somatic cell count and returned to the initial level shortly after restriction period. The present {\textquoteleft}high through-put{\textquoteright} analytical method may be beneficial in future studies to phenotype modifications in mammary energy metabolism and milk fat synthesis, for which IDH activity may be a biomarker.",

keywords = "Goat, Isocitrate, Isocitrate dehydrogenase-1, Lipogenesis, Milk enzyme",

author = "Torben Larsen and R Rupp and Friggens, {N C} and Pires, {J A A}",

year = "2022",

month = aug,

doi = "10.1016/j.animal.2022.100593",

language = "English",

volume = "16",

journal = "Animal",

issn = "1751-7311",

publisher = "Elsevier B.V.",

number = "8",

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TY - JOUR

T1 - Fluorometric determination of isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP + dependent) in ruminant milk

AU - Larsen, Torben

AU - Rupp, R

AU - Friggens, N C

AU - Pires, J A A

PY - 2022/8

Y1 - 2022/8

N2 - The enzyme isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP+ dependent) located in the mammary cell cytosol mediates the synthesis of the majority of reducing equivalents for the energetically demanding milk fat and cholesterol synthesis in mammary cell cytosol. The present article presents a novel fluorometric method for quantification of the activity of this enzyme (IDH) in ruminant milk without pretreatment of the sample. Further, 493 goat milk samples – harvested before, during and after a nutritional restriction – were analysed for IDH activity i) with addition of extra substrate (isocitrate), and ii) with the intrinsic isocitrate solely. The IDH activity ranged from 0.22 to 15.4 units [nano moles product/(ml * min)] (un-supplemented) and from 0.22 to 45.6 units (isocitrate supplemented). The IDH activity increased considerably in milk during the nutritional restriction period concomitant with the increase in the metabolite isocitrate concentration and somatic cell count and returned to the initial level shortly after restriction period. The present ‘high through-put’ analytical method may be beneficial in future studies to phenotype modifications in mammary energy metabolism and milk fat synthesis, for which IDH activity may be a biomarker.

AB - The enzyme isocitrate dehydrogenase (EC 1.1.1.42; 1; NADP+ dependent) located in the mammary cell cytosol mediates the synthesis of the majority of reducing equivalents for the energetically demanding milk fat and cholesterol synthesis in mammary cell cytosol. The present article presents a novel fluorometric method for quantification of the activity of this enzyme (IDH) in ruminant milk without pretreatment of the sample. Further, 493 goat milk samples – harvested before, during and after a nutritional restriction – were analysed for IDH activity i) with addition of extra substrate (isocitrate), and ii) with the intrinsic isocitrate solely. The IDH activity ranged from 0.22 to 15.4 units [nano moles product/(ml * min)] (un-supplemented) and from 0.22 to 45.6 units (isocitrate supplemented). The IDH activity increased considerably in milk during the nutritional restriction period concomitant with the increase in the metabolite isocitrate concentration and somatic cell count and returned to the initial level shortly after restriction period. The present ‘high through-put’ analytical method may be beneficial in future studies to phenotype modifications in mammary energy metabolism and milk fat synthesis, for which IDH activity may be a biomarker.

KW - Goat

KW - Isocitrate

KW - Isocitrate dehydrogenase-1

KW - Lipogenesis

KW - Milk enzyme

U2 - 10.1016/j.animal.2022.100593

DO - 10.1016/j.animal.2022.100593

M3 - Journal article

C2 - 35870267

SN - 1751-7311

VL - 16

JO - Animal

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