Species differences in the sites of cleavage of pro-lactase to lactase supports lack of selective pressure

Zecca, Laura; Mesonero, José E.; Gloor, Sergio M.; Semenza, Giorgio

doi:10.1016/s0167-4838(99)00201-0

Cited by 3 publications

(1 citation statement)

References 31 publications

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“…LCT shows a four-fold internal homology, which suggests that it arose by two duplication events (24). Pro-lactase is proteolytically processed to a smaller protein (30)(31)(32) and two of the four homologous regions occur in the cleaved pro-portion of the molecule, which does not have a catalytic function, but probably has a chaperone function, in that it seems to play a role in transporting the molecule to the cell surface (33)(34)(35)(36)(37)(38). There is one active site in each of the domains of the mature protein.…”

Section: Biochemistry and Genetics Of Lactasementioning

confidence: 99%

Lactose intolerance: genetics of lactase polymorphisms, diagnosis and novel therapy

Sequeira¹,

Kaur²,

Chintamaneni³

et al. 2014

Biomedical Reviews

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Lactose intolerance is a common disorder affecting an individual's ability to digest lactose present in milk or any food product. Lactose intolerance is caused by the deficiency of β-galactosidase (lactase) in the digestive tract. Diagnosis of lactose intolerance is not so simple and straightforward clinically. Many biochemical and genetic tests have been developed for the determination of lactose intolerance. Several case reports indicate wherein subjects have self-diagnosed being lactose intolerant. There is an emerging link of this disorder with human gene polymorphism, where genetic basis has been used as a diagnostic tool. The high prevalence of this condition among children and adults has compelled the production of lactose-free foods. Additionally, external enzyme supplementation has been looked at as an alternative protective mechanism in lactose intolerant subjects. This review highlights the genetic variants of lactase polymorphism and theranostic (therapeutic and diagnostic) strategies for lactose intolerance.

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Section: Biochemistry and Genetics Of Lactasementioning

confidence: 99%

Lactose intolerance: genetics of lactase polymorphisms, diagnosis and novel therapy

Sequeira¹,

Kaur²,

Chintamaneni³

et al. 2014

Biomedical Reviews

View full text Add to dashboard Cite

show abstract

Lactase

Semenza

Mantei

2002

Wiley Encyclopedia of Molecular Medicine

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Genetics of Lactase Persistence and Lactose Intolerance

2003

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The enzyme lactase that is located in the villus enterocytes of the small intestine is responsible for digestion of lactose in milk. Lactase activity is high and vital during infancy, but in most mammals, including most humans, lactase activity declines after the weaning phase. In other healthy humans, lactase activity persists at a high level throughout adult life, enabling them to digest lactose as adults. This dominantly inherited genetic trait is known as lactase persistence. The distribution of these different lactase phenotypes in human populations is highly variable and is controlled by a polymorphic element cis-acting to the lactase gene. A putative causal nucleotide change has been identified and occurs on the background of a very extended haplotype that is frequent in Northern Europeans, where lactase persistence is frequent. This single nucleotide polymorphism is located 14 kb upstream from the start of transcription of lactase in an intron of the adjacent gene MCM6. This change does not, however, explain all the variation in lactase expression.

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Species differences in the sites of cleavage of pro-lactase to lactase supports lack of selective pressure

Cited by 3 publications

References 31 publications

Lactose intolerance: genetics of lactase polymorphisms, diagnosis and novel therapy

Lactose intolerance: genetics of lactase polymorphisms, diagnosis and novel therapy

Lactase

Genetics of Lactase Persistence and Lactose Intolerance

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