title: Human cutaneous melanoma expresses a significant phosphate-dependent glutaminase activity: a comparison with the surrounding skin of the same patient.
abstract: The protein content and the activity and type of phosphate-dependent glutaminase were determined in freshly pigmented lesions obtained from human melanoma and adjacent skin. Significant phosphate-dependent glutaminase activity was found in both the melanoma and non-pigmented adjacent skin areas. A comparison between the pigmented and adjacent skin areas suggests the occurrence of gradual metabolic changes that result in an increased protein content in the centre of the neoplasia. The presence of a kidney-type glutaminase (K(m) of 2-5 mm) indicates a high sensitivity of the melanoma to variations in glutamine plasma levels (0.6 to 1 mm). These data lead us to postulate that glutamine supply is an important factor for melanoma cell proliferation, being a source of nitrogen for DNA and RNA synthesis. The intense neovascularization observed in melanoma ensures the oxygen supply that is required for glutamine oxidation. These findings support the proposition that glutamine is an important fuel for melanoma.
authors.affiliation: Federal University of São Paulo (UNIFESP), Brazil.
authors.forename: Darwin Pinheiro Machado
authors.initials: DP
authors.lastname: Zacharias
authors.forename: Manuela Maria Ramos
authors.initials: MM
authors.lastname: Lima
authors.forename: Alcione Lescano
authors.initials: AL
authors.lastname: Souza
authors.forename: Ivan Dunshee
authors.initials: ID
authors.lastname: de Abranches Oliveira Santos
authors.forename: Milvia
authors.initials: M
authors.lastname: Enokiara
authors.forename: Nilceo
authors.initials: N
authors.lastname: Michalany
authors.forename: Rui
authors.initials: R
authors.lastname: Curi
mesh_terms: D005972:Glutaminase / Q000378:metabolism*; D006801:Humans; D008545:Melanoma / Q000201:enzymology* / Q000473:pathology; D011379:Prognosis; D012878:Skin Neoplasms / Q000201:enzymology* / Q000473:pathology
chemical_list: D005972:Glutaminase