Serine hydroxymethyltransferase: evidence for its existence in rat lens

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6374898

Geller, A; Jernigan, H Jr

Previous studies by Jernigan using cultured adult rat lens incubated with N/sup 15/-glu or gln indicated that the enzyme hydroxymethyltransferase (SHMT) was present in lens. SHMT catalyzes the reversible formation of 5,10-methylene tetrahydrofolate and glycine from serine and tetrahydrofolate (THFA) and is the major point of entry of carbons into the one-carbon folate pool. Using a combination of direct enzyme assay and mass spectroscopy, conclusive evidence for the presence of the enzyme has been obtained. After incubation of cultured adult rat lenses for up to 24 hrs with N/sup 15/-labeled serine substantial amounts of label were found in glycine. In contrast, after a 24 hr incubation with N/sup 15/-glycine, lesser amounts of label were found in serine. The data confirm the reversibility of the SHMT reaction in vivo. SHMT activity has been unequivocally demonstrated in rat lens using a newly developed assay based on the binding of 5,10-methylene THFA to DEAE-cellulose paper. SHMT activity was highest in lenses from young animals and decreased with increasing age; for example, the specific activity was 3.98 units/mg on day one and 0.23 units/mg at day 30. The assay requires THFA, is linear with respect to the time and protein. The properties of the lenticular cystosolic SHMT have been studied.

• Research Organization: Univ. of Tennessee, Memphis
• OSTI ID: 6374898
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AGE DEPENDENCE
AMINO ACIDS
ANIMALS
BIOASSAY
BODY
BODY AREAS
CARBOXYLIC ACIDS
CHEMICAL PROPERTIES
CRYSTALLINE LENS
ENZYME ACTIVITY
ENZYMES
EYES
FACE
GLYCINE
HEAD
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MASS SPECTROSCOPY
NITROGEN 15
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RATS
RODENTS
SENSE ORGANS
SPECTROSCOPY
STABLE ISOTOPES
TRACER TECHNIQUES
TRANSFERASES
VERTEBRATES