Evidence for the existence of a glutamine cycle in Neurospora crassa is reviewed. Through this cycle glutamine is converted into glutamate by glutamate synthase and catabolized by the glutamine transaminase-omega-amidase pathway, the products of which (2-oxoglutarate and ammonium) are the substrates for glutamate dehydrogenase-NADPH, which synthesizes glutamate. In the final step ammonium is as...

Freshwater fish Cirrhinus mrigala were exposed to lethal concentration (5 mg/L) for 1,2,3,4 days and sublethal concentration (1 mg/L) for 1,7,14,21 days of cypermethrin to examine the enzymes activity, in functionally three different tissues namely, gill, liver and muscle. Activities of Aspartate aminotransferase (AAT), Alanine aminotransferase (AlAT) and Glutamate dehydrogenase (GDH) increased...

freshwater fish cirrhinus mrigala were exposed to lethal concentration (5 mg/l) for 1,2,3,4 days and sublethal concentration (1 mg/l) for 1,7,14,21 days of cypermethrin to examine the enzymes activity, in functionally three different tissues namely, gill, liver and muscle. activities of aspartate aminotransferase (aat), alanine aminotransferase (alat) and glutamate dehydrogenase (gdh) increased...

Roberts, D. B. (University of Cambridge, Cambridge, England). Immunochemical and enzymatic studies on glutamate dehydrogenase and a related mutant protein from Neurospora crassa. J. Bacteriol. 91:1888-1895. 1966.-When an investigation was made of the inhibition of Neurospora glutamate dehydrogenase by bivalent and univalent antibodies, it was shown that the enzyme inhibition is not complete eve...

1. The apparent Michaelis constants of the glutamate dehydrogenase (EC 1.4.1.3), the glutamate-oxaloacetate transaminase (EC 2.6.1.1) and the glutaminase (EC 3.5.1.2) of rat brain mitochondria derived from non-synaptic (M) and synaptic (SM2) sources were studied. 2. The kinetics of oxygen uptake of both populations of mitochondria in the presence of a fixed concentration of malate and various c...

The only exogenous substrates oxidized by mitochondria isolated from the flight muscle of the Japanese beetle (Popillia japonica) are proline, pyruvate and glycerol 3-phosphate. The highest rate of oxygen consumption is obtained with proline. The oxidation of proline leads to the production of more NH3 than alanine, indicating a functioning glutamate dehydrogenase (EC 1.4.1.2). Studies of mitoc...

In a concurrent study of the serum activity of glutamate-oxalacetate transaminase (GO-T), glutamate-pyruvate transaminase (GP-T), lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) in normal newborn infants ranges of normal values for these enzymes have been defined (King and Morris, 1961). In the present report the activity of these enzymes in relation to neonatal jaundice and in prema...

Differential diagnosis of acute viral hepatitis, persistent chronic hepatitis, aggressive chronic hepatitis, and post-necrotic cirrhosis can reasonably be achieved on the basis of three well-known liver-function tests: aspartate aminotransferase, alanine aminotransferase, and glutamate dehydrogenase. With use of principal-component analysis, these four liver diseases can be characterized by two...

The kinetic properties of enzymes are often reported using the apparent KM and Vmax appropriate to the standard Michaelis-Menten enzyme. However, this model is inappropriate to enzymes that have more than one substrate or where the rate expression does not apply for other reasons. Consequently, it is desirable to have a means of estimating the appropriate kinetic parameters from the apparent va...

A simple, convenient, and rapid method for determining ammonia in plasma by the glutamate dehydrogenase reaction is described for the centrifugal analyzer. The measuring principle is fixed-time, with NADH as the coenzyme. ADP is added to stabilize glutamate dehydrogenase and prevent interference from endogenous plasma ADP. The reaction is linear to 400 mumol of ammonia per liter. The plasma sam...