diff --git a/pkg/core/dao/dao.go b/pkg/core/dao/dao.go
index 6995612ce..c2563f24d 100644
--- a/pkg/core/dao/dao.go
+++ b/pkg/core/dao/dao.go
@@ -7,12 +7,14 @@ import (
 	"errors"
 	"fmt"
 	iocore "io"
+	"math/big"
 	"sync"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/util"
@@ -387,6 +389,14 @@ func (dao *Simple) PutStorageItem(id int32, key []byte, si state.StorageItem) {
 	dao.Store.Put(stKey, si)
 }
 
+// PutBigInt serializaed and puts the given integer for the given id with the given
+// key into the given store.
+func (dao *Simple) PutBigInt(id int32, key []byte, n *big.Int) {
+	var buf [bigint.MaxBytesLen]byte
+	stData := bigint.ToPreallocatedBytes(n, buf[:])
+	dao.PutStorageItem(id, key, stData)
+}
+
 // DeleteStorageItem drops a storage item for the given id with the
 // given key from the store.
 func (dao *Simple) DeleteStorageItem(id int32, key []byte) {
diff --git a/pkg/core/native/management.go b/pkg/core/native/management.go
index 92de9015d..b30266624 100644
--- a/pkg/core/native/management.go
+++ b/pkg/core/native/management.go
@@ -601,8 +601,7 @@ func (m *Management) getNextContractID(d *dao.Simple) (int32, error) {
 	id := bigint.FromBytes(si)
 	ret := int32(id.Int64())
 	id.Add(id, intOne)
-	si = bigint.ToPreallocatedBytes(id, si)
-	d.PutStorageItem(m.ID, keyNextAvailableID, si)
+	d.PutBigInt(m.ID, keyNextAvailableID, id)
 	return ret, nil
 }
 
diff --git a/pkg/core/native/native_neo.go b/pkg/core/native/native_neo.go
index 7e601d3c8..cde774216 100644
--- a/pkg/core/native/native_neo.go
+++ b/pkg/core/native/native_neo.go
@@ -440,7 +440,7 @@ func (n *NEO) PostPersist(ic *interop.Context) error {
 				}
 				cache.gasPerVoteCache[cs[i].Key] = *tmp
 
-				ic.DAO.PutStorageItem(n.ID, key, bigint.ToBytes(tmp))
+				ic.DAO.PutBigInt(n.ID, key, tmp)
 			}
 		}
 	}
@@ -1088,8 +1088,7 @@ func (n *NEO) modifyVoterTurnout(d *dao.Simple, amount *big.Int) error {
 	}
 	votersCount := bigint.FromBytes(si)
 	votersCount.Add(votersCount, amount)
-	si = bigint.ToPreallocatedBytes(votersCount, si)
-	d.PutStorageItem(n.ID, key, si)
+	d.PutBigInt(n.ID, key, votersCount)
 	return nil
 }
 
@@ -1218,5 +1217,5 @@ func (n *NEO) putGASRecord(dao *dao.Simple, index uint32, value *big.Int) {
 	key := make([]byte, 5)
 	key[0] = prefixGASPerBlock
 	binary.BigEndian.PutUint32(key[1:], index)
-	dao.PutStorageItem(n.ID, key, bigint.ToBytes(value))
+	dao.PutBigInt(n.ID, key, value)
 }
diff --git a/pkg/core/native/native_nep17.go b/pkg/core/native/native_nep17.go
index e0963530e..6a2c42c02 100644
--- a/pkg/core/native/native_nep17.go
+++ b/pkg/core/native/native_nep17.go
@@ -108,8 +108,7 @@ func (c *nep17TokenNative) getTotalSupply(d *dao.Simple) (state.StorageItem, *bi
 }
 
 func (c *nep17TokenNative) saveTotalSupply(d *dao.Simple, si state.StorageItem, supply *big.Int) {
-	si = state.StorageItem(bigint.ToPreallocatedBytes(supply, si))
-	d.PutStorageItem(c.ID, totalSupplyKey, si)
+	d.PutBigInt(c.ID, totalSupplyKey, supply)
 }
 
 func (c *nep17TokenNative) Transfer(ic *interop.Context, args []stackitem.Item) stackitem.Item {
diff --git a/pkg/core/native/oracle.go b/pkg/core/native/oracle.go
index 0f819104a..505a2680c 100644
--- a/pkg/core/native/oracle.go
+++ b/pkg/core/native/oracle.go
@@ -355,8 +355,7 @@ func (o *Oracle) RequestInternal(ic *interop.Context, url string, filter *string
 	itemID := bigint.FromBytes(si)
 	id := itemID.Uint64()
 	itemID.Add(itemID, intOne)
-	si = bigint.ToPreallocatedBytes(itemID, si)
-	ic.DAO.PutStorageItem(o.ID, prefixRequestID, si)
+	ic.DAO.PutBigInt(o.ID, prefixRequestID, itemID)
 
 	// Should be executed from the contract.
 	_, err := ic.GetContract(ic.VM.GetCallingScriptHash())
diff --git a/pkg/core/native/util.go b/pkg/core/native/util.go
index a9d85ba9e..0666b9eac 100644
--- a/pkg/core/native/util.go
+++ b/pkg/core/native/util.go
@@ -37,7 +37,7 @@ func putConvertibleToDAO(id int32, d *dao.Simple, key []byte, conv stackitem.Con
 }
 
 func setIntWithKey(id int32, dao *dao.Simple, key []byte, value int64) {
-	dao.PutStorageItem(id, key, bigint.ToBytes(big.NewInt(value)))
+	dao.PutBigInt(id, key, big.NewInt(value))
 }
 
 func getIntWithKey(id int32, dao *dao.Simple, key []byte) int64 {
diff --git a/pkg/encoding/bigint/bench_test.go b/pkg/encoding/bigint/bench_test.go
new file mode 100644
index 000000000..411a10b85
--- /dev/null
+++ b/pkg/encoding/bigint/bench_test.go
@@ -0,0 +1,15 @@
+package bigint
+
+import (
+	"math/big"
+	"testing"
+)
+
+func BenchmarkToPreallocatedBytes(b *testing.B) {
+	v := big.NewInt(100500)
+	buf := make([]byte, 4)
+
+	for i := 0; i < b.N; i++ {
+		_ = ToPreallocatedBytes(v, buf[:0])
+	}
+}
diff --git a/pkg/encoding/bigint/bigint.go b/pkg/encoding/bigint/bigint.go
index 35081992a..ffb11a591 100644
--- a/pkg/encoding/bigint/bigint.go
+++ b/pkg/encoding/bigint/bigint.go
@@ -1,7 +1,6 @@
 package bigint
 
 import (
-	"encoding/binary"
 	"math/big"
 	"math/bits"
 
@@ -109,36 +108,26 @@ func ToBytes(n *big.Int) []byte {
 func ToPreallocatedBytes(n *big.Int, data []byte) []byte {
 	sign := n.Sign()
 	if sign == 0 {
-		return data
+		return data[:0]
 	}
 
 	if sign < 0 {
 		n.Add(n, bigOne)
 		defer func() { n.Sub(n, bigOne) }()
 		if n.Sign() == 0 { // n == -1
-			return append(data, 0xFF)
+			return append(data[:0], 0xFF)
 		}
 	}
 
-	var ws = n.Bits()
+	lb := n.BitLen()/8 + 1
 
-	lb := len(ws) * wordSizeBytes
 	if c := cap(data); c < lb {
-		data = make([]byte, lb, lb+1)
+		data = make([]byte, lb)
 	} else {
 		data = data[:lb]
 	}
-	data = wordsToBytes(ws, data)
-
-	size := len(data)
-	for ; data[size-1] == 0; size-- {
-	}
-
-	data = data[:size]
-
-	if data[size-1]&0x80 != 0 {
-		data = append(data, 0)
-	}
+	_ = n.FillBytes(data)
+	slice.Reverse(data)
 
 	if sign == -1 {
 		for i := range data {
@@ -148,17 +137,3 @@ func ToPreallocatedBytes(n *big.Int, data []byte) []byte {
 
 	return data
 }
-
-func wordsToBytes(ws []big.Word, bs []byte) []byte {
-	if wordSizeBytes == 8 {
-		for i := range ws {
-			binary.LittleEndian.PutUint64(bs[i*wordSizeBytes:], uint64(ws[i]))
-		}
-	} else {
-		for i := range ws {
-			binary.LittleEndian.PutUint32(bs[i*wordSizeBytes:], uint32(ws[i]))
-		}
-	}
-
-	return bs
-}