Homocarnosinase: A hog kidney dipeptidase with a broader specificity than carnosinase

Lenney, James F.; Kan, Siu-Chow; Siu, Kingsum; Sugiyama, Glen H.

doi:10.1016/0003-9861(77)90349-6

Cited by 35 publications

(11 citation statements)

References 33 publications

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“…When we added dithiothreitol (2 mM) to samples of human CSF, no increase in free GABA concentration was evident at room temperature for up to 72 h, in agreement with the in vitvo inhibitory effect of this reagent on homocarnosinase activity (Kish et al, 1979). In addition, the absence of homocarnosinase activity in rat brain (Lenney et al, 1977) is consistent with our observation that free GABA is not formed from homocarnosine in CSF of this species.…”

Section: Discussionsupporting

confidence: 88%

Artifactual Increases in the Concentration of Free GABA in Samples of Human Cerebrospinal Fluid Are Due to Degradation of Homocarnosine

Grove

Schechter

Tell

et al. 1982

Journal of Neurochemistry

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Samples of untreated human cerebrospinal fluid (CSF) were kept at room temperature (20 +/- 1 degree C) up to 72 h, and changes in gamma-aminobutyric acid (GABA) and homocarnosine contents were measured. The concentration of free GABA increased with time, and concomitantly a similar decrease occurred in the concentration of homocarnosine. Total GABA after hydrolysis (present in human CSF at concentrations of 40-100 times that of free GABA) did not change. After 2 h the increase in CSF GABA for seven subjects ranged from 42 to 244 pmol/ml. The rate of increase in CSF GABA was positively correlated with the initial homocarnosine concentration. Approximately 5% per h of the initial homocarnosine content was degraded during the first 7 h at room temperature; thereafter the rate gradually decreased. No free GABA was formed in CSF frozen at -70 degrees C for 10 days. When this CSF was restored to room temperature, the formation of free GABA from homocarnosine occurred at essentially the same rate as that observed in fresh CSF. These results demonstrate that the well-known artifactual increase in GABA concentration of untreated human CSF depends on the concentration of homocarnosine. The rapidity of this increase (up to 2 pmol/ml/min) could account for disparities among CSF free GABA concentrations previously reported from normal subjects. It is suggested that measurement of concentrations of total GABA in the CSF would provide a better index of human brain GABA concentration than determination of CSF free GABA.

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Section: Discussionsupporting

confidence: 88%

Artifactual Increases in the Concentration of Free GABA in Samples of Human Cerebrospinal Fluid Are Due to Degradation of Homocarnosine

Grove

Schechter

Tell

et al. 1982

Journal of Neurochemistry

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“…The synthesis has been demonstrated to occur in different tissues, including muscle (Bakardjiev and Bauer, 1994;Bauer and Schulz, 1994) and brain (Horinishi et al, 1978). A carnosinase (EC 3.4.13.3) and an homocarnosinase responsible for the degradation of these compounds have also been identified in different tissues (Rosemberg, 1960;Harding and Margolis, 1976;Lenney, 1976;Lenney et al, 1977;Ng et al, 1977;Ng and Marshall, 1978;Harding and O'Fallon, 1979;Margolis et al, 1983;Margolis and Grillo, 1984b). The aminoacyl-histidine dipeptides are usually abundant in excitable tissues, such as muscle and nervous tissue.…”

Section: Carnosine and Carnosine-related Dipeptidesmentioning

confidence: 99%

Carnosine-related dipeptides in the mammalian brain

Bonfanti

Peretto

Marchis

et al. 1999

Progress in Neurobiology

186

107

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-Carnosine and structurally related dipeptides are a group of histidine-containing molecules widely distributed in vertebrate organisms and particularly abundant in muscle and nervous tissue. Although many theories have been proposed, the biological function(s) of these compounds in the nervous system remains enigmatic. The purpose of this article is to review the distribution of carnosine-related dipeptides in the mammalian brain, with particular reference to some cell populations wherein these molecules have been demonstrated to occur very recently. The high expression of carnosine in the mammalian olfactory receptor neurons led to infer that this dipeptide could play a role as a neurotransmitter/modulator in olfaction. This prediction, which has not yet been fully demonstrated, does not explain the localization of carnosine-related dipeptides in other cell types, such as glial and ependymal cells. A recent demonstration of high carnosine-like immunoreactivity in the subependymal layer of rodents, an area of the forebrain which shares with the olfactory neuroepithelium the occurrence of continuous neurogenesis during adulthood, supports the hypothesis that carnosine-related dipeptides could be implicated in some forms of structural plasticity. However, the particular distribution of these molecules in the subependymal layer, along with their expression in glial/ependymal cell populations, suggests that they are not directly linked to cell migration or cell renewal. In the absence of a unified theory about the role of carnosine-related dipeptides in the nervous system, some common features shared by different cell populations of the mammalian brain which contain these molecules are discussed.

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“…2). Lenney et al (1977) also noted the influence of divalent metal cations on the pH optimum of the proteolytic enzymes; the maximal activity of the homocarnosinase with Co 2 + was observed at pH 7.2, whereas with Mn 2 + the optimum pH was 8.5. Our earlier studies (Luberda et al 1992b) described the influence of Zn 2 + ions at the concentration range 10-5 M-10-3M and of Ca 2 + ions at the concentration of 10-4 M on the proteolytic activity of the purified hatching enzyme of C. albula.…”

Section: Discussionmentioning

confidence: 99%

Some proteolytic properties of hatching liquid in the sea trout, Salmo trutta m. trutta L.

Luberda¹,

Strzeżek²,

Luczynski³

1993

Fish Physiol Biochem

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Proteolytic activity of sea trout hatching liquid was examined towards casein and azocazein as a function of pH and temperature. The optimum pH for caseinolytic and azocaseinolytic activities were 9.4, and 9.0, respectively. At alkaline pH the enzyme was activated by low concentrations of Zn(2+) ions (10(-5) M). Maximum proteolytic activity of the hatching liquid was observed at 25°C. Temperatures exceeding 30°C caused a rapid reduction in enzyme activity. Proteolytic activity observed at 10°C was approximately 50% of that observed at 25°C. In general, a pseudo-Arrhenius plot indicated a Q10 of 1.6 between 6 and 25°C.

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Homocarnosinase: A hog kidney dipeptidase with a broader specificity than carnosinase

Cited by 35 publications

References 33 publications

Artifactual Increases in the Concentration of Free GABA in Samples of Human Cerebrospinal Fluid Are Due to Degradation of Homocarnosine

Artifactual Increases in the Concentration of Free GABA in Samples of Human Cerebrospinal Fluid Are Due to Degradation of Homocarnosine

Carnosine-related dipeptides in the mammalian brain

Some proteolytic properties of hatching liquid in the sea trout, Salmo trutta m. trutta L.

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