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Biomedical subjects

M E Geroch

Publications and source records attributed to M E Geroch.

10 recordsLinked to original sources
PubMed1975

A highly basic small protein associated with spermatogenesis in the human testis.

A very basic and acid-soluble small protein was isolated in the pure form from specimens of human testes that displayed histologic evidence of normal spermatogenesis. The protein is virtually indistinguishable in its electrophoretic properties from a testis-specific basic protein that has been previously described in a number of other eutherian mammalian species. The homogeneous human testicular basic protein is rich in arginine, lysine, and serine, and is devoid of cyst(e)ine, phenylalanine, glutamate, glutamine, isoleucine, and tryptophan. Its amino acid composition is extremely close to that of a testis-specific basic protein previously described in the rat. The basic protein from human testis is electrophoretically distinct from the principal basic chromosomal protein of human spermatozoa and could not be detected in ejaculated human spermatozoa by the procedure used to extract the chromosomal basic protein.

Chromatography, Gel↗
PubMed1970

Rat mammary-gland acetyl-coenzyme A carboxylase interaction with milk fatty acids.

1. Highly purified rat mammary-gland acetyl-CoA carboxylase was inhibited by milk obtained from rats 12h after their young were weaned. 2. All the inhibitory activity was found in the particulate fraction (R(105)) obtained on centrifuging the milk. It could be extracted from milk fraction R(105) with acetone and identified as a complex mixture of non-esterified fatty acids, present in high concentration (nearly 10mm) in the milk. 3. Inhibition of acetyl-CoA carboxylase was observed at low concentrations (0.2-20mum) of several of these fatty acids when fresh fully active enzyme was used. Enzyme that had been partly inactivated by aging, or by storing in the absence of citrate, was stimulated by low concentrations but inhibited by high concentrations of fatty acids. 4. Various experiments suggested that fatty acids produce irreversible inactivation of acetyl-CoA carboxylase. 5. The effects of palmitoyl-CoA on mammary-gland acetyl-CoA carboxylase were found to resemble those of fatty acids, except that palmitoyl-CoA was effective at lower concentration. 6. The effect of milk fraction R(105) was tested on six other enzymes previously shown to decline to various extents after weaning. Although several of these enzymes were affected by unfractionated milk fraction R(105), none was significantly inhibited by the acetone extract or by low concentrations of lauric acid. 7. The findings are consistent, both qualitatively and quantitatively, with a regulatory mechanism whereby milk fatty acids shut off fatty acid synthesis in the mammary gland after weaning by inhibiting acetyl-CoA carboxylase.

Acetone↗