diff --git a/pkg/core/blockchain_test.go b/pkg/core/blockchain_test.go
index 14c687a19..079b4efd3 100644
--- a/pkg/core/blockchain_test.go
+++ b/pkg/core/blockchain_test.go
@@ -124,8 +124,10 @@ func TestAddBlock(t *testing.T) {
 	_, err = bc.persist(false)
 	require.NoError(t, err)
 
+	key := make([]byte, 1+util.Uint256Size)
+	key[0] = byte(storage.DataExecutable)
 	for _, block := range blocks {
-		key := storage.AppendPrefix(storage.DataExecutable, block.Hash().BytesBE())
+		copy(key[1:], block.Hash().BytesBE())
 		_, err := bc.dao.Store.Get(key)
 		require.NoErrorf(t, err, "block %s not persisted", block.Hash())
 	}
diff --git a/pkg/core/storage/store.go b/pkg/core/storage/store.go
index b6cfe80bf..0812a5f08 100644
--- a/pkg/core/storage/store.go
+++ b/pkg/core/storage/store.go
@@ -1,7 +1,6 @@
 package storage
 
 import (
-	"encoding/binary"
 	"errors"
 	"fmt"
 
@@ -112,23 +111,6 @@ func (k KeyPrefix) Bytes() []byte {
 	return []byte{byte(k)}
 }
 
-// AppendPrefix appends byteslice b to the given KeyPrefix.
-// AppendKeyPrefix(SYSVersion, []byte{0x00, 0x01}).
-func AppendPrefix(k KeyPrefix, b []byte) []byte {
-	dest := make([]byte, len(b)+1)
-	dest[0] = byte(k)
-	copy(dest[1:], b)
-	return dest
-}
-
-// AppendPrefixInt append int n to the given KeyPrefix.
-//   AppendPrefixInt(SYSCurrentHeader, 10001)
-func AppendPrefixInt(k KeyPrefix, n int) []byte {
-	b := make([]byte, 4)
-	binary.BigEndian.PutUint32(b, uint32(n))
-	return AppendPrefix(k, b)
-}
-
 func seekRangeToPrefixes(sr SeekRange) *util.Range {
 	var (
 		rang  *util.Range
diff --git a/pkg/core/storage/store_test.go b/pkg/core/storage/store_test.go
index a07b97ece..7191e46ad 100644
--- a/pkg/core/storage/store_test.go
+++ b/pkg/core/storage/store_test.go
@@ -3,48 +3,9 @@ package storage
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
-var (
-	prefixes = []KeyPrefix{
-		DataExecutable,
-		DataMPT,
-		STStorage,
-		IXHeaderHashList,
-		SYSCurrentBlock,
-		SYSCurrentHeader,
-		SYSVersion,
-	}
-
-	expected = []uint8{
-		0x01,
-		0x03,
-		0x70,
-		0x80,
-		0xc0,
-		0xc1,
-		0xf0,
-	}
-)
-
-func TestAppendPrefix(t *testing.T) {
-	for i := 0; i < len(expected); i++ {
-		value := []byte{0x01, 0x02}
-		prefix := AppendPrefix(prefixes[i], value)
-		assert.Equal(t, KeyPrefix(expected[i]), KeyPrefix(prefix[0]))
-	}
-}
-
-func TestAppendPrefixInt(t *testing.T) {
-	for i := 0; i < len(expected); i++ {
-		value := 2000
-		prefix := AppendPrefixInt(prefixes[i], value)
-		assert.Equal(t, KeyPrefix(expected[i]), KeyPrefix(prefix[0]))
-	}
-}
-
 func TestBatchToOperations(t *testing.T) {
 	b := &MemBatch{
 		Put: []KeyValueExists{