Effect of eyestalk extract on UDPG-glycogen transglucosylase in crab muscle

Effect of eyestalk extract on UDPG-glycogen transglucosylase in crab muscle

Life Sciences No . 5, pp . 209-z11, 1962 . Great Britain. Pergamon Press Ltd. Printed in EFFECT OF EYESTALK EXTRACT qV UDPG-GLYCOGEN TRANSGLUCQSYLA...

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Life Sciences No . 5, pp . 209-z11, 1962 . Great Britain.

Pergamon Press Ltd.

Printed in

EFFECT OF EYESTALK EXTRACT qV UDPG-GLYCOGEN TRANSGLUCQSYLASE IN CRAB MUSCLE D .H . Wang and B .T . Scheer Department of Biology, University of Oregon, Eugene, Oregon (Received 19 February 1962 ; in revised form

3

April 1962)

GLYCOGEN transglucosylase (synthetase) activity, measured by the method of Leloir and Goldemberg l , has been found in all the tissues of crabs tested, except for the thoracic ganglion (Table 1) . activity .

Muscle tissue has, in general, the highest

Tissues were prepared by homogenizing in water in the cold .

The homo-

genate was centrifuged at 3000 g for 10 min, and the supernatant was centrifuged at 1200 g for 10 min. for all enzyme assays .

The supernatant from the second centrifugation was used The enzyme is activated by glucose-6-phosphate, but not

to the extent reported for rat muscle enzyme by Leloir et a1 . 2

These observations

extend the list of organisms which contain this important enzyme system to include crustaceans ; R.R . Traut (personal communication) has also found the enzyme in lobster muscle .

The results also confirm the suggestion, based on physiologi-

cal evidence, that glycogen is synthesized in crustaceans by the glycogen synthetase pathway . 3 The activity of a mixture of eyestalk and leg muscle enzyme preparations should, in principle, be the sum of the activities of the two .

In general, the

total activity, and the specific activity per mg N, in such mixtures was only 50 per cent of the predicted value ; a typical experiment is reported in Table 2 . The eyestalk preparation therefore appears to contain a factor which inhibits the activity of the glycogen transglucosylase system .

The presence of a factor

in eyestalk extracts which causes an increase in blood reducing value,*

and

specifically in the fermentable sugar of the blood5 '6 has been known for some time .

Scheer and Scheer6 showed that eyestalk removal results in increased

tissue utilization of glucose in spiny lobsters, and Scheer~' g has shown that 209

210

UDPG~LYCOGEN TRANSGLUCOSYLASE IN CRAB MUSCLE

No .S

TABLE 1 Activity of UDPG-Glycogen Transglucosylase in different Tissues . Reaction Mixture for UDF Formation contains UDPG 0 .25

moles,

G-6-P 0 .5 umoles, EDTA 0 .25 Pmoles, Glycogen 0 .4 mg, Glycine Buffer pH 8 .5, 7.5 umoles, Total Volume 0 .05 ml

Species

Cancer magister

Specific activity moles UDP/mg N per hr

Tissue

heart

5 .90

leg muscle

6 .60

hepatopa~ncreas

0 .53

thoracic ganglion

0

male reproductive tract

0 .64

eyestalk

0 .38

Hemigrapsus nu dus

skeletal muscle

4 .26

Astacus cambarus

abdominal muscle

1 .80

chela muscle

7 .40

TABLE 2 UDPG-Glycogen Transglucosylase Activities of Mixtures of Muscle and Eyestalk Preparations from Cancer magister .

Conditions as

in Table 1

Tissue preparation Eyestalk

Activity m~nnole UDP formed

L

pecific activity m~unole UDP/mg N

4.4

Muscle

94 .4

50 .0

2910 .0

Eyestalk + muscle

27 .2

Predicted activity of mixture

43 .7

544

85 .0

No .5

UDPG-GLYCOGEN TRANSGLUCOSYLASE IN CRAB MUSCLE

211

the same operation results in an increase in glycogen stores in several crustacean species .

The available infonnation therefore suggests that the point

of action of the diabetogenic factor of the crustacean eyestalk may be the glycogen transglucosylase system .

In this connection it is of interest that

epinephrine decreases transglucosylase activity in mammalian muscle, 9 and insulin increases the activity of this enzyme in the absence of glucose-6phosphate in the rat diaphragm . l0 Supported by Grant G-13107 from the National Science Foundation . Abbreviations :

EDTA = ethylene diamine tetraacgtic acid ; G-6-P = glucose-6-phosphate ; UDP = uridine diphosphate ; UDPG = uridine diphosphate glucose . References

1.

L .F . LELOIR and S .H . GOLDEMBERG, J. Biol . Chem . ~, 919 (1960) .

2.

L .F . LELOIR, J .M . OLAVARRIA, S .H . GOLDEMHERG and H . CARMINATTI, Arch . Biochem. Biophvs . $l, 508 (1959) .

3.

V .R . MEENAKSHI and B .T . SCHEER, Comp . Biochem . Phvsiol . ~, 30 (1961) .

4.

A .A . ABRAMOWITZ, F .L . HISAW and D.N . PAPANDREA, Biol . Bull . Woods Hole 86, 1 (1944) "

5.

L .H . KLEINHOLZ and B .C . LITTLE, Hiol . Hull . Woods Hole ~, 218 (1949) "

6.

B .T . SCHEER and M .A .R . SCHEER, Phvsiol . Comp . Oecol . ~, 198 (1951) .

7.

B .T . SCHEER, Hiol . Bull . Woods Hole. llb, 175 (1959) "

8.

B .T . SCFE:ER, Comp . Biochem. Phvsiol . 1, 3 (1960) .

9.

E . BELICOPITOW, arch . Biochem . Biophvs . ~, 457 (1961) .

10 .

C . VILLAR-PALASI and J. LARNER, Arch . Biochem. Biophvs . ~, 436 (1961) .